Method for reducing ototoxicity in pediatric patients receiving platinum-based chemotherapy

ABSTRACT

Described herein is a method for eliminating or reducing ototoxicity in patients receiving a platinum based chemotherapeutic. In particular, are methods of reducing ototoxicity in a pediatric patient. The methods described herein include administering an effective amount of sodium thiosulfate to a patient in need thereof to reduce ototoxicity.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.15/826,243, filed Nov. 29, 2017, the entire contents of which is herebyincorporated herein by reference.

GOVERNMENT INTEREST

This invention was made with support by the United States governmentunder R01-CA137488 and R01-NS044687 awarded by the National Institutesof Health. The United States government has certain rights in theinvention.

TECHNICAL FIELD

Described herein is a method for eliminating or reducing ototoxicity inpatients receiving a platinum based chemotherapeutic. In particular, aremethods of reducing ototoxicity in a pediatric patient.

BACKGROUND

Platinum based therapeutics are highly important components of treatmentregimens used in a variety of pediatric malignancies includingneuroblastoma, hepatoblastoma, medulloblastoma, osteosarcoma, malignantgerm cell tumors and nasopharyngeal carcinomas. Unfortunately, atcommonly used doses and schedules, platinum based therapeutics, such ascisplatin and carboplatin, frequently cause hearing loss that isprogressive, bilateral, irreversible, and often accompanied by tinnitus.Platinum chemotherapeutic based hearing loss can affect all hearingfrequencies owing to the death of cochlear outer hair cells.

These toxicities can be dose-limiting and is often clinicallysignificant, especially in young children who are critically dependentupon normal hearing for cognitive, psychosocial and speech development.Approximately 40% of children develop cisplatin-induced hearing losswith nearly 100% incidence for certain vulnerable groups. The effects ofeven mild hearing loss in pediatrics is substantial with, inter alia,reduced language acquisition, learning, academic performance, social andemotional development, and life quality. Thus, there is a need for safeand effective methods for treating pediatric patients to reduceototoxicity and hearing loss in these patients that do not compromisethe efficacy of the platinum-based therapeutic.

SUMMARY

Described herein are methods for reducing ototoxicity in patients havingreceived a platinum based chemotherapeutic. In particular, are methodsfor reducing ototoxicity in pediatric patients. The methods includeadministering an effective amount of sodium thiosulfate (STS) to thepatient following administration of the platinum based chemotherapeutic.As described herein, the administration of STS was found to notadversely affect the efficacy of the platinum based chemotherapeutic anddecreased the incidence and severity of ototoxicity in pediatricpatients.

One embodiment is a method of reducing ototoxicity in a patient having acancer and receiving a platinum based chemotherapeutic comprisingadministering an effective amount of sodium thiosulfate to the patient.

Another embodiment is a method of prophylactically treating a patienthaving a cancer and receiving a platinum based chemotherapeutic toreduce a likelihood of the patient incurring ototoxicity comprisingadministering an effective amount of sodium thiosulfate to the patient.

Another embodiment is a method of reducing long term ototoxicity in apatient having a cancer and receiving a platinum based chemotherapeuticcomprising administering an effective amount of sodium thiosulfate tothe patient.

Another embodiment is a method of reducing a concentration of cisplatinin an aural cavity of a patient having a cancer and receiving a platinumbased chemotherapeutic comprising administering an effective amount ofsodium thiosulfate to the patient, wherein substantially no cisplatin isdetectable in the aural cavity and wherein the patient administered thesodium thiosulfate is less susceptible to incurring ototoxicity from theplatinum based chemotherapeutic.

Another embodiment is a method of inhibiting ototoxic effects associatedwith an administration of platinum based chemotherapeutic compounds in apatient comprising administering an effective amount of sodiumthiosulfate to the patient.

In some embodiments described herein, the patient carries has singlenucleotide polymorphism in a gene ACYP2 at locus rs1872328. In someembodiments, the patient administered sodium thiosulfate is about 20% toabout 75% less likely to experience ototoxicity than a patient notadministered sodium thiosulfate. In some embodiments, the patientadministered sodium thiosulfate is about 50% less likely to experienceototoxicity than a patient not administered sodium thiosulfate. In someembodiments ototoxicity comprises hearing loss, dysequilibrium,tinnitus, or hearing sensitivity or combinations thereof.

In some embodiments described herein, the platinum basedchemotherapeutic is selected from cisplatin, carboplatin, oxaliplatin,nedaplatin, triplatin tetranitrate, phenanthriplatin, picoplatin, andsatraplatin. In some embodiments, the platinum based chemotherapeutic iscisplatin.

In some embodiments, the cancer being treated is localized ordisseminated. In some embodiments, the cancer being treated islocalized. In some embodiments, the cancer being treated is selectedfrom a germ cell tumor, hepatoblastoma, medulloblastoma, neuroblastoma,and osteosarcoma. In some embodiments, the cancer being treated ishepatoblastoma. In some embodiments, the cancer being treated is astandard risk cancer, intermediate risk cancer, or high risk cancer. Insome embodiments, the cancer being treated is a standard risk cancer oran intermediate risk cancer. In some embodiments, the cancer beingtreated is standard risk or intermediate risk hepatoblastoma.

In some embodiments, the sodium thiosulfate is administered prior to,concurrently with, or after the administration of the platinum basedchemotherapeutic. In some embodiments, the sodium thiosulfate isadministered about 0.5 hours to about 10 hours after the administrationof the platinum based chemotherapeutic. In some embodiments, the sodiumthiosulfate is administered intravenously. In some embodiments, theeffective amount of sodium thiosulfate is from about 5 g/m² to about 25g/m² per cycle of the platinum based chemotherapeutic. In someembodiments, the patient is being treated with a dose of about 1 mg/kgto about 5 mg/kg or about 10 mg/m² to about 300 mg/m² per cycle of theplatinum based chemotherapeutic.

In some embodiments described herein, ototoxicity is determined by oneor more criteria comprising: a tinnitus functional index, Brock grading,American Speech-Language-Hearing Association criteria, or InternationalSociety of Pediatric Oncology Boston Ototoxicity Scale. In someembodiments ototoxicity is determined by measuring a hearing loss at oneor more frequencies comprising 500 Hz, 1,000 Hz, 2,000 Hz, 4,000 Hz, or8,000 Hz or a combination of frequencies thereof, wherein a change inhearing is computed relative to baseline measures prior to the patientreceiving a platinum based chemotherapeutic or sodium thiosulfate orboth.

In some embodiments described herein, ototoxicity is determined by oneor more criteria comprising: a). a reduction in hearing measured by a 20dB loss at a single frequency; b). a reduction in hearing measured by a10 dB loss at two consecutive frequencies; c). loss of response at threeconsecutive test frequencies where responses were previously obtained;d). a reduction in bilateral high-frequency hearing characterized by:i). a <40 dB hearing loss at all frequencies, which indicates a grade 0or minimal hearing loss; ii). a ≥40 dB hearing loss at 8,000 Hz only,which indicates a grade 1 or mild hearing loss; iii). a ≥40 dB hearingloss at 4,000 Hz and above, which indicates a grade 2 or moderatehearing loss; iv). a ≥40 dB hearing loss at 2,000 Hz and above, whichindicates a grade 3 or marked hearing loss; v). a ≥40 dB hearing loss at1,000 Hz and above, which indicates a grade 4 or severe hearing loss; ore). a reduction in hearing characterized by: i). a ≤20 dB hearing lossat all frequencies, which indicates a grade 0 hearing loss; ii). a >20dB HL above 4,000 Hz, which indicates a grade 1 hearing loss; iii).a >20 dB HL at 4,000 Hz and above, which indicates a grade 2 hearingloss; iv). a >20 dB HL at 2,000 Hz or 3,000 Hz, which indicates a grade3 hearing loss; v). a >40 dB HL at 2,000 Hz and above, which indicates agrade 1 hearing loss, or f). an improvement in a tinnitus functionalindex; and wherein a change in hearing is computed relative to baselinemeasures prior to the patient receiving a platinum basedchemotherapeutic or sodium thiosulfate or both. In some embodiments, thepediatric patient administered sodium thiosulfate has a reduction inototoxicity assessed by criterion d) described above compared to apediatric patient not administered sodium thiosulfate.

In some embodiments described herein, the administration of sodiumthiosulfate to a patient does not lead to increased serum creatinine ora reduction in glomerular filtration rate compared to a patient notadministered sodium thiosulfate. In some embodiments, the administrationof sodium thiosulfate to a patient does not affect relapse free survivalor overall survival compared to a patient not administered sodiumthiosulfate. In some embodiments, the administration of sodiumthiosulfate to a patient does not lead to increased incidence of one ormore adverse events comprising febrile neutropenia, infection,hypomagnesemia, hypernatremia, vomiting, or nausea.

In some embodiments described herein, ototoxicity is measured at a timeof at least 4 weeks following the administration of the platinum basedchemotherapeutic and sodium thiosulfate to a patient.

In some embodiments described herein, the patient is a pediatricpatient. In some embodiments described herein, the pediatric patient is1 week of age to 18 years of age. In some embodiments, the pediatricpatient is about 12 years of age or less. In some embodiments, thepediatric patient is about 5 years of age or less. In some embodiments,the pediatric patient is about 2 years of age or less. In someembodiments, the pediatric patient is about 1 year of age or less.

Another embodiment is a dosing regimen for treating hepatoblastoma in apediatric patient comprising: a). administering a dose of about 1 mg/kgto about 5 mg/kg or about 10 mg/m² to about 300 mg/m² per cycle ofcisplatin; b). administering about 5 g/m² to about 25 g/m² of sodiumthiosulfate per cycle of the cisplatin, wherein the sodium thiosulfateis administered from about 2 hours to about 6 hours after theadministration of the cisplatin; and wherein the dosing regimen achievesa reduction in ototoxicity when dosed to a pediatric patient compared toa dosing regimen not including the sodium thiosulfate, which is dosed toa pediatric patient, wherein ototoxicity is determined by one or morecriteria selected from: a). a reduction in hearing measured by a 20 dBloss at a single frequency; b). a reduction in hearing measured by a 10dB loss at two consecutive frequencies; c). loss of response at threeconsecutive test frequencies where responses were previously obtained;d). a reduction in bilateral high-frequency hearing characterized by thecriteria: i). a <40 dB hearing loss at all frequencies, which indicatesa grade 0 or minimal hearing loss; ii). a ≥40 dB hearing loss at 8,000Hz only, which indicates a grade 1 or mild hearing loss; iii). a ≥40 dBhearing loss at 4,000 Hz and above, which indicates a grade 2 ormoderate hearing loss; iv). a ≥40 dB hearing loss at 2,000 Hz and above,which indicates a grade 3 or marked hearing loss; v). a ≥40 dB hearingloss at 1,000 Hz and above, which indicates a grade 4 or severe hearingloss; or e). a reduction in hearing characterized by the criteria: i). a≤20 dB hearing loss at all frequencies, which indicates a grade 0hearing loss; ii). a ≥20 dB HL above 4,000 Hz, which indicates a grade 1hearing loss; iii). a >20 dB HL at 4,000 Hz and above, which indicates agrade 2 hearing loss; iv). a >20 dB HL at 2,000 Hz or 3,000 Hz, whichindicates a grade 3 hearing loss; v). a >40 dB HL at 2,000 Hz and above,which indicates a grade 1 hearing loss; wherein a change in hearing iscomputed relative to baseline measures prior to the patient receiving aplatinum based chemotherapeutic or sodium thiosulfate or both.

Another embodiment is method of reducing ototoxicity in a pediatricpatient of about 12 years of age and under having a standard risk or anintermediate risk hepatoblastoma and receiving a dose of about 1 mg/kgto about 5 mg/kg or about 10 mg/m² to about 300 mg/m² per cycle ofcisplatin, the method comprising administering about 5 g/m² to about 25g/m² of sodium thiosulfate per cycle of the cisplatin about six hoursafter the administration of the cisplatin, wherein ototoxicity isdetermined by one or more criteria selected from: a). a reduction inhearing measured by a 20 dB loss at a single frequency; b). a reductionin hearing measured by a 10 dB loss at two consecutive frequencies; c).loss of response at three consecutive test frequencies where responseswere previously obtained; d). a reduction in bilateral high-frequencyhearing characterized by the criteria: i). a <40 dB hearing loss at allfrequencies, which indicates a grade 0 or minimal hearing loss; ii). a≥40 dB hearing loss at 8,000 Hz only, which indicates a grade 1 or mildhearing loss; iii). a ≥40 dB hearing loss at 4,000 Hz and above, whichindicates a grade 2 or moderate hearing loss; iv). a ≥40 dB hearing lossat 2,000 Hz and above, which indicates a grade 3 or marked hearing loss;v). a ≥40 dB hearing loss at 1,000 Hz and above, which indicates a grade4 or severe hearing loss; or e). a reduction in hearing characterized bythe criteria: i). a ≤20 dB hearing loss at all frequencies, whichindicates a grade 0 hearing loss; ii). a >20 dB HL above 4,000 Hz, whichindicates a grade 1 hearing loss; iii). a >20 dB HL at 4,000 Hz andabove, which indicates a grade 2 hearing loss; iv). a >20 dB HL at 2,000Hz or 3,000 Hz, which indicates a grade 3 hearing loss; v). a >40 dB HLat 2,000 Hz and above, which indicates a grade 1 hearing loss; wherein achange in hearing is computed relative to baseline measures prior to thepatient receiving a platinum based chemotherapeutic or sodiumthiosulfate or both; and wherein the administration of sodiumthiosulfate does not substantively affect relapse free survival oroverall survival compared to a pediatric patient not administered sodiumthiosulfate; and wherein the administration of sodium thiosulfate doesnot lead to substantively increased incidence of one or more adverseevents comprising febrile neutropenia, infection, hypomagnesemia,hypernatremia, vomiting, or nausea.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram of patient eligibility and testing arms, eithercontrol or STS treated and the number of patients included at primaryendpoint analysis for the study of Example 1.

FIG. 2 is a table providing the demographics of patients enrolled in thestudy of Example 1.

FIG. 3 is a table providing the categorization of patient tumor typesboth in the control (observation) arm and the STS arm of the study ofExample 1.

FIG. 4 is a table providing additional categorization information forpatient tumor types both in the control (observation) arm and the STSarm and associated event free survival (EFS) and overall survival (OS)of the study of Example 1.

FIG. 5A is a Kaplan-Meier curve showing event free survival and overallsurvival for all 126 patients for the study of Example 1; the meanfollow-up was 2.9 years.

FIG. 5B is a Kaplan-Meier curve showing event free survival and overallsurvival for all 126 patients for the study of Example 1; the meanfollow-up was 2.9 years.

FIG. 6 is a bar graph showing hearing loss for either the observation(control) arm or the STS treatment arm for the study of Example 1.

FIG. 7 is a bar graph showing hearing loss for either the observation(control) arm or the STS treatment arm with patients segmented by ageeither <5 or ≥5 years of age for the study of Example 1.

FIG. 8 is a bar graph showing hearing loss for either the observation(control) arm or the STS treatment arm with patients segmented by eitherlocalized or disseminated tumor for the study of Example 1.

FIG. 9 is a bar graph showing hearing loss for either the observation(control) arm or the STS treatment arm with patients segmented by tumortype for the study of Example 1.

FIG. 10 is a graph showing the mean hearing threshold in dB for eitherobservation (control) arm or the STS treatment arm showing hearingthreshold pre-treatment and post-treatment for the study of Example 1.

FIG. 11 is a table providing the demographics of patients with localizedtumors enrolled in the study of Example 1.

FIG. 12 is a table providing the demographics of patients with localizedtumors enrolled in the study of Example 1.

FIG. 13A is a Kaplan-Meier curve showing event free survival and overallsurvival segmented by patients having a localized tumor only for thestudy of Example 1.

FIG. 13B is a Kaplan-Meier curve showing event free survival and overallsurvival segmented by patients having a localized tumor only for thestudy of Example 1.

FIG. 14 is a table providing the characteristics of the tumors ofpatients with disseminated disease enrolled in the study of Example 1.

FIG. 15 is a table providing the demographics of the patients withdisseminated disease enrolled in the study of Example 1.

FIG. 16A is a Kaplan-Meier curve showing event free survival segmentedby patients having a disseminated tumor only for the study of Example 1.

FIG. 16B is a Kaplan-Meier curve showing event overall survivalsegmented by patients having a disseminated tumor only for the study ofExample 1.

FIG. 17 is a Kaplan-Meier curve showing post-hoc analysis of event freesurvival excluding the group of other tumors for all patients for thestudy of Example 1.

FIG. 18 is a Kaplan-Meier curve showing post-hoc analysis of overallsurvival excluding the group of other tumors for all patients for thestudy of Example 1.

FIG. 19 is a table providing the demographics of patients with germ celltumors enrolled in the study of Example 1.

FIG. 20A is a Kaplan-Meier curve showing analysis of event free survivalof patients having germ-cell tumors for the study of Example 1.

FIG. 20B is a Kaplan-Meier curve showing analysis of overall survival ofpatients having germ-cell tumors for the study of Example 1.

FIG. 21 is a table providing the demographics of patients withhepatoblastoma tumors enrolled in the study of Example 1.

FIG. 22A is a Kaplan-Meier curve showing analysis of event free survivalof patients having hepatoblastoma tumors for the study of Example 1.

FIG. 22B is a Kaplan-Meier curve showing analysis of overall survival ofpatients having hepatoblastoma tumors for the study of Example 1.

FIG. 23 is a table providing the demographics of patients withmedulloblastoma tumors enrolled in the study of Example 1.

FIG. 24A is a Kaplan-Meier curve showing analysis of event free survivalof patients having medulloblastoma tumors for the study of Example 1.

FIG. 24B is a Kaplan-Meier curve showing analysis of overall survival ofpatients having medulloblastoma tumors for the study of Example 1.

FIG. 25 is a table providing the demographics of patients withneuroblastoma tumors enrolled in the study of Example 1.

FIG. 26A is a Kaplan-Meier curve showing analysis of event free survivalof patients having neuroblastoma tumors for the study of Example 1.

FIG. 26B is a Kaplan-Meier curve showing analysis of overall survival ofpatients having neuroblastoma tumors for the study of Example 1.

FIG. 27 is a table providing the demographics of patients withosteosarcoma tumors enrolled in the study of Example 1.

FIG. 28A is a Kaplan-Meier curve showing analysis of event free survivalof patients having osteosarcoma tumors for the study of Example 1.

FIG. 28B is a Kaplan-Meier curve showing analysis of overall survival ofpatients having osteosarcoma tumors for the study of Example 1.

FIG. 29A is a Kaplan-Meier curve showing post-hoc analysis of event freesurvival excluding the group of other tumors for all patients for thestudy of Example 1.

FIG. 29B is a Kaplan-Meier curve showing post-hoc analysis of overallsurvival excluding the group of other tumors for all patients for thestudy of Example 1.

FIG. 30 is a table providing the demographics of patients under the ageof 5 enrolled in the study of Example 1.

FIG. 31 is a table providing the characteristics of the tumors forpatients under the age of 5 enrolled in the study of Example 1.

FIG. 32A is a Kaplan-Meier curve showing analysis of event free survivalof patients under the age of 5 for the study of Example 1.

FIG. 32B is a Kaplan-Meier curve showing analysis of overall survival ofpatients under the age of 5 for the study of Example 1.

FIG. 33 is a table providing the demographics of patients greater thanor equal to the age of 5 enrolled in the study of Example 1.

FIG. 34 is a table providing the characteristics of the tumors forpatients greater than or equal to the age of 5 enrolled in the study ofExample 1.

FIG. 35A is a Kaplan-Meier curve showing analysis of event free survivalof patients greater than or equal to the age of 5 for the study ofExample 1.

FIG. 35B is a Kaplan-Meier curve showing analysis of overall survival ofpatients greater than or equal to the age of 5 for the study of Example1.

FIG. 36 is a schematic showing the study design for the study of Example2.

FIG. 37 is a flow diagram of patient eligibility and testing arms,either control or STS treated and the number of patients included atprimary endpoint analysis for the study of Example 2.

FIG. 38 is a table providing the demographics of patients enrolled inthe study of Example 2.

FIG. 39 is a table that shows the incidence rate of adverse eventsincluding grade 3 or 4 febrile neutropenia, invention, hypomagnesemia,hypernatremia, vomiting, and nausea both for the control arm (cisplatintreated only) and the cisplatin+STS arm for the study of Example 2.

FIG. 40 is a bar graph showing the hearing results according to Brockgrade ≥1 by treatment arm, either cisplatin or cisplatin+STS for thestudy of Example 2.

FIG. 41 is a bar graph showing the hearing results according to Brockgrades 0-4 by treatment arm, either cisplatin or cisplatin+STS for thestudy of Example 2.

FIG. 42A is a Kaplan-Meier curve showing analysis of event free survivalof patients separated by treatment arm for enrolled in the study ofExample 2; the median follow-up time was 52 months.

FIG. 42B is a Kaplan-Meier curve showing analysis of overall survival ofpatients separated by treatment arm for enrolled in the study of Example2; the median follow-up time was 52 months.

DETAILED DESCRIPTION

The term “patient” refers to any subject including mammals and humans.The patient may have a disease or suspected of having a disease and assuch is being treated with a drug. In some instances, the patient is amammal, such as a dog, chicken, cat, horse, or primate. In someinstances, the term “patient,” as used herein, refers to a human (e.g.,a man, a woman, or a child). In some instances, the term “patient,” asused herein, refers to laboratory animal of an animal model study. Thepatient or subject may be of any age, sex, or combination thereof. Insome embodiments as described further herein, the patient is treatedwith a platinum based chemotherapeutic such as cisplatin followed byadministration of the drug sodium thiosulfate.

The term “pediatric patient” refers to a pediatric mammal and human. Insome instances, the patient is a mammal, such as a dog, chicken, cat,horse, or primate or a puppy, a chic, a kitten, a colt or filly, or aninfant. The pediatric patient may be of any ethnicity or sex. Thepediatric patient may be of any age, which would be understood to theperson of skill in the art to be a pediatric patient in medicine and inveterinary medicine. For example, a human pediatric patient may be aneonate up to 21 years of age. A newborn pediatric is understood to bebirth to 1 month of age; an infant is 1 month to 2 years of age; a childis 2 years to 12 years of age; and an adolescent is 12 to 21 years ofage. The pediatric patient may have a disease or suspected of having adisease and as such is being treated with a drug. In some embodiments asdescribed further herein, the pediatric patient is treated with aplatinum based chemotherapeutic such as cisplatin followed byadministration of the drug sodium thiosulfate.

The term “ototoxicity” refers to any type of toxicity that affects theear. The toxicity may be to the cochlea (e.g., cochleotoxicity),cochlear hair cells, the auditory nerve, or the vestibular system or anyof these systems found in the ear or any of these systems incombination. The toxicity can manifest as hearing loss, sensorineuralhearing loss, dysequilibrium, tinnitus, or hearing sensitivity orcombinations thereof. When referring to hearing loss, the amount oftoxicity causing the hearing loss can be mild, moderate, severe,profound, or total resulting in complete deafness. Alternatively, thehearing loss may present at specific frequencies including both high andlow frequencies and all iterations of frequencies normal to mammalianhearing. The toxicity can be unilateral, bilateral, bilateral symmetric,or bilateral asymmetric with one ear being more affected than the other.

The terms “biological sample” or “sample” as used herein refers to asample obtained or derived from a patient. By way of example, abiological sample comprises a material selected from the groupconsisting of body fluids, blood, whole blood, plasma, serum, mucussecretions, saliva, cerebrospinal fluid (CSF), bronchoalveolar lavagefluid (BALF), urine, fluids of the eye (e.g., vitreous fluid, aqueoushumor), lymph fluid, lymph node tissue, spleen tissue, bone marrow, andfluid from the auditory cavity.

As described herein, it was found that STS reduces ototoxicity inpediatric patients being treated with a platinum based chemotherapeutic.It was further surprisingly found that children being under the age of12 have higher rates of ototoxicity and children under the age of 5 areeven more at risk. It was further found that the administration of STSafter a platinum based chemotherapeutic (i.e., cisplatin) was able tosignificantly reduce ototoxicity in these pediatric patients. Inparticular, it was discovered that STS could reduce the severity ofototoxicity, such as Brock grade 2 and 3 ototoxicities. Further, it wasidentified that the total amount of cisplatin exposure or cumulativedose did not interfere with STS mediated otoprotection. In addition, itwas discovered that STS is highly suitable as an otoprotective drug whenused in conjunction with local (non-disseminated) cancers.

STS is a water-soluble thiol compound with reducing agent properties andis commercially available as an established antidote for acute cyanidepoisoning. STS is a reducing agent and has been used in oncology forpreventing cisplatin nephrotoxicity, carboplatin ototoxicity and as anantidote for extravasation of various chemotherapy agents. The mechanismby which sodium thiosulfate reduces the nephrotoxicity caused bycisplatin and the ototoxicity by carboplatin is not fully understood.Proposed mechanisms of action involve its thiol group, which allow it toact as a free radical scavenger and/or by covalent binding inactivatingthe platinum compound. Sodium thiosulfate reacts irreversibly withcisplatin to form Pt(S203)₄ when the drugs are given simultaneously orin close approximation. It is also believed that sodium thiosulfateprotects against nephrotoxicity by reducing delivery of cisplatin to thekidneys and by neutralizing cisplatin in the kidneys where sodiumthiosulfate is highly concentrated. Following IV injection, sodiumthiosulfate is distributed throughout the extracellular fluid. Somesodium thiosulfate is converted to sulfate in the liver. Up to 95% isexcreted unchanged in the urine. The biological half-life is 0.65 hours(range: dependent on dose 16.5-182 minutes). When given intravenously,STS is rapidly excreted by the kidney.

Whilst not being bound by any theory, it is believed that the biologicaleffects of STS in preventing cisplatin-induced ototoxicity include STSbinding of electrophilic platinum molecules, scavenging of reactiveoxygen species and its concentration in cochlear endolymph. Thus, asingle effective dosage scavenges all remaining platinumchemotherapeutic so that it cannot accumulate and cause damage to thecochlear hair. Despite its cisplatin binding properties, the resultsfrom two phase III clinical trials further demonstrated that theefficacy of cisplatin based chemotherapeutics in pediatric patients wasnot affected when the STS was administered after administration ofcisplatin.

In addition, STS does not adversely affect the efficacy of several othernon-platinum based chemotherapeutics including doxorubicin andetoposide. In vitro studies of small cell lung cancer cell culturesshowed no reduction of cytotoxicity for etoposide with either theimmediate or delayed addition of STS followed by incubation for 72hours. Similar studies showed no reduction of anti-tumor activity by STSfor doxorubicin, carmustine (BCNU), paclitaxel or methotrexate. Owing toits ability to scavenge free platinum containing compounds, STS wasextensively tested in the clinic, as further described in the Examplesherein, and found to be a highly effective otoprotective compound forpediatric patients.

Described herein are methods for reducing ototoxicity in patient (i.e.,pediatric patients) having a cancer and who are receiving a platinumbased chemotherapeutic for treatment of the cancer. The methods includeadministering an effective amount of STS to the patient. It was foundthat STS significantly reduces the risk of ototoxicity particularly inpediatric patient populations. Therefore, one embodiment, describedherein is a method for reducing ototoxicity in a pediatric patienthaving a cancer and receiving a platinum based chemotherapeuticcomprising administering an effective amount of STS to the pediatricpatient. In some aspects, the pediatric patient already has incurredototoxicity and the administration of STS reduces the amount of futureototoxicity incurred by the pediatric patient.

The risk of a pediatric patient having detectable ototoxicity, forexample, hearing loss measured by the Brock scale of ≥1 is significantlyreduced by treatment with STS following the administration of acisplatinum based chemotherapeutic. The risk of ototoxicity is relevantto a pediatric patient not receiving STS. Thus, in some embodiments, thelikelihood of a pediatric patient incurring any ototoxicity is reducedby STS administration by about 10% to about 100%, about 30% to about 90%or about 40% to about 70%, including each integer within the specifiedranges. In some embodiments, the risk of a pediatric patient incurringany ototoxicity is reduced by STS administration by about 10%, about20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%,about 90%, or even about 100%. In some aspects, the risk of a pediatricpatient incurring ototoxicity according to ASHA-defined hearing losscriteria is about 50%.

Similarly, treatment of a pediatric patient with STS can further reducelong-term ototoxicity in pediatric patients having a cancer andreceiving a platinum based chemotherapeutic. It is known that followingtreatment with STS, pediatric patients can exhibit ototoxicity weeks,months, or even years following the succession of treatment with theplatinum based chemotherapeutic. Thus, another embodiment describedherein is a method of reducing long-term ototoxicity in a pediatricpatient having a cancer and receiving a platinum based chemotherapeuticcomprising administering an effective amount of sodium thiosulfate tothe pediatric patient.

As described above, it is thought that platinum based chemotherapeuticagents, such as cisplatin, exert ototoxic effects by concentrating inthe aural cavity of a patient (e.g., a pediatric patient). It is furthercontemplated herein that STS can reduce the amount of platinum basedchemotherapeutic agent in the aural cavity by binding to the agent andreducing its accumulation in the aural cavity. Another embodimentdescribed herein is a method of reducing a concentration of cisplatin inan aural cavity of a pediatric patient having a cancer and receiving aplatinum based chemotherapeutic comprising administering an effectiveamount of sodium thiosulfate to the pediatric patient. In some aspects,the concentration of cisplatin is reduced by in the aural cavity byabout 50%, about 60%, about 70%, about 80%, about 90%, or about 100%compared to a pediatric patient receiving a platinum basedchemotherapeutic and not receiving STS. In some aspects, theconcentration of cisplatin is not detectable in the aural cavity. Insome aspects, the patient administered STS is less susceptible toincurring ototoxicity because the amount of platinum basedchemotherapeutic in the aural cavity is reduced. Methods for detectingcisplatin in the aural cavity include extracting a sample from the auralcavity and measuring the amount of cisplatin present in the sample, forexample, through high performance liquid chromatography (HPLC) or othermethods known in the art.

The methods described herein are also useful for preventing orinhibiting ototoxicity in a pediatric patient having a cancer and who isreceiving a platinum based chemotherapeutic for treatment of the cancer.It was found that pediatric patients are particularly susceptible toincurring ototoxicity and prophylactically treating the pediatricpatient can reduce the ototoxicity in the pediatric patient. Therefore,another embodiment described herein is a method of prophylacticallytreating a pediatric patient having a cancer and receiving a platinumbased chemotherapeutic with an effective amount of STS, wherein thetreatment reduces a likelihood of the pediatric patient incurringototoxicity.

It has been determined that certain genetic variations can cause anincreased likelihood of a pediatric patient having ototoxicity and theseverity of ototoxicity in the patient. The genes TPMT, COMT, and ABCC3have been shown to put pediatric patients at a greater risk forincurring ototoxicity (see Ross, C. J. et al. Genetic variants in TPMTand COMT are associated with hearing loss in children receivingcisplatin chemotherapy. Nat. Genet. 41, 1345-1349 (2009) and Pussegoda,K. et al. Replication of TPMT and ABCC3 genetic variants is highlyassociated with cisplatin-induced hearing loss in children. Clin.Pharmacol. Ther. 94, 243-251 (2013)). In addition, it has more recentlybeen shown that single nucleotide polymorphism in the ACYP2 gene at thelocus rs1872328 are associated with cisplatin-based ototoxicity (see Xu,K. et al. Common variants in ACYP2 influence susceptibility tocisplatin-induced hearing loss. Nat. Genetics. 47(3), 263-266 (2015).Thus, in some embodiments a pediatric patient receiving a cisplatinbased chemotherapeutic is identified as being at high risk for having agenetic variation in one or more of the genes TPMT, COMT, ABCC3, andACYP2 and treated with STS to reduce the likelihood, prevent, inhibit,or treat ototoxicity.

In some embodiments described herein, the pediatric patient has a cancerand is receiving a platinum based chemotherapeutic. In some otherembodiments, the pediatric patient does not yet have a diagnosed cancerbut is being treated with a platinum based chemotherapeutic. Anyplatinum-based drug would be expected to be scavenged by STS and reduceototoxicity. Thus, in some embodiments, the platinum basedchemotherapeutic comprises cisplatin, carboplatin, oxaliplatin,nedaplatin, triplatin tetranitrate, phenanthriplatin, picoplatin, andsatraplatin. In some aspects, the platinum based chemotherapeutic iscisplatin.

The amount of platinum based chemotherapeutic that a pediatric patientis recieving is determined by the treating physician, the type ofdisease or cancer that is being treated, and the age or weight of thepediatric patient. In some aspects, the amount of platinum basedchemotherapeutic (e.g., cisplatin) per cycle of administration is about1 mg/kg to about 5 mg/kg, including each integer within the specifiedrange. In some aspects, the amount of platinum based chemotherapeutic(e.g., cisplatin) per cycle of administration is about 10 mg/m² to about300 mg/m², 10 mg/m² to about 100 mg/m², or about 40 mg/m² to about 80mg/m², including each integer within the specified ranges.

Many cancers are treated with platinum based chemotherapeutics inpediatric patients, for which STS may be administered. In some aspectsof the embodiments described herein, a pediatric patient has a cancerthat is being treated with a platinum based chemotherapeutic followed bySTS, wherein the cancer is localized or disseminated. In some aspects,the cancer is low-risk, medium risk, or high risk (e.g., metastatic)cancer. In some aspects, the cancer is low-risk or medium-risk. In someaspects, the cancer being treated with a platinum based chemotherapeuticis localized and is not disseminated or metastatic. Non-limiting andexemplary cancers that can be treated with a platinum basedchemotherapeutic followed by STS comprise germ cell tumors (e.g.,testicular cancer or ovarian cancer), hepatoblastoma, medulloblastoma,neuroblastoma, and osteosarcoma. In some aspects, a pediatric patienthas a hepatoblastoma cancer and is being treated with a platinum basedchemotherapeutic and STS. In some aspects, a pediatric patient has alow-risk or medium-risk hepatoblastoma cancer and is being treated witha platinum based chemotherapeutic and STS.

In some embodiments, the STS is administered to a pediatric patientreceiving treatment with a platinum based chemotherapeutic agent priorto, concurrently with, or after the administration of the platinum basedchemotherapeutic. In some aspects, the STS is administered 0 minutes orabout 5 minutes to about 96 hours after the administration of theplatinum based chemotherapeutic, including each integer of time withinthe specified range. In some aspects, the STS is administered about 30minutes to about 24 hours, about 1 hour to about 24 hours, about 1 toabout 12 hours, about 1 hour to about 8 hours, or about 4 hours to about7 hours after the administration of the platinum based chemotherapeutic,including each integer of time within the specified ranges. In oneaspect, the STS is administered about 6 hours after the administrationof the platinum based chemotherapeutic.

The administration of STS may be carried out in any way that is knownfor administering STS. For example, STS may be administered parenterallyor enterally. If administered parenterally, the STS can be administeredintravenously (IV), subcutaneously (SC), or intramuscularly (IM).Enteral administration includes oral, sublingual or rectal. Inembodiments, the STS is administered intravenously.

An effective amount of STS is an amount of STS, which prevents, reduces,or inhibits ototoxicity in a pediatric patient receiving a platinumbased chemotherapeutic. In some embodiments, the amount of STSadministered is about 0.5 g/m² to about 50 g/m², about 1 g/m² to about25 g/m² or 15 g/m² to about 25 g/m², including each integer within thespecified ranges. In some embodiments, the amount of STS administered isabout 1 g/m², about 2 g/m², about 4 g/m², about 6 g/m², about 8 g/m²,about 10 g/m², about 15 g/m², about 20 g/m², about 25 g/m², about 30g/m², about 40 g/m², or about 50 g/m². The effective amount of STS isadministered prior to, concomitantly with, or following each cycle ofplatinum based chemotherapy.

Some additional embodiments described herein are dosing regimens fortreating a cancer in a pediatric patient, which include administering aplatinum based chemotherapeutic and STS. One embodiment is a dosingregimen for treating hepatoblastoma in a pediatric patient that includesadministering a dose of about 1 mg/kg to about 5 mg/kg or about 10 mg/m²to about 300 mg/m² per cycle of a platinum based chemotherapeutic,including each integer within the recited range; and also administeringabout 5 g/m² to about 25 g/m² of STS per cycle of the platinum basedchemotherapeutic, including each integer within the specified ranges. Inone aspect, the STS is administered from about 2 hours to about 6 hoursafter the administration of the platinum based chemotherapeutic,including each integer within the recited range.

The measurement of ototoxicity following administration of the platinumbased chemotherapeutic and STS should be carried out after a period timefollowing the last treatment with the platinum based chemotherapeuticand STS. In some aspects, the ototoxicity is measured after a timeperiod of at least 3 days to about 3 months, 1 week to about 3 months, 1week to about 2 months, or 1 week to about 4 weeks following the lasttreatment with the platinum based chemotherapeutic and STS, includingeach integer within the specified ranges of time. In one aspect, theototoxicity is measured after a time period of at least 4 weeks from thelast treatment with the platinum based chemotherapeutic and STS.

The measurement of ototoxicity following administration of the platinumbased chemotherapeutic and STS can be carried out multiple times and upto years following the last administration of STS and the platinum basedchemotherapeutic. Audiometric methods for measuring hearing loss arewell known to those of ordinary skill in the art and are used inconjunction with various scales to assess ototoxicity. Assessingototoxicity allows, for example, the assessment of any potentialototoxicity or long-term prevention of ototoxicity by STS. Theassessment of ototoxicity can be determined by one or more criteriaknown in the art. For example, ototoxicity may include assessment by thetinnitus functional index, Brock grading, Children's Cancer Group 1996study scale, Children's Hospital Boston scale, the Chang andChinosornvatana scale, the American Speech-Language-Hearing Associationcriteria, the Common Terminology Criteria for Adverse Events scale(CTCAE pediatric grading), or the International Society of PediatricOncology Boston Ototoxicity Scale or a combination of these scales (seeGurney, J. G. et al., Oncology, J. Clin. Onc. 30(19), 2303-2306 (2012).The measurement of hearing function should in most cases be completedprior to treatment with an ototoxic drug such as a cisplatin or anotherplatinum based chemotherapeutic. This establishes a baseline measure ofhearing function to which any potential ototoxic effects can becompared. Thus, changes in hearing or increase or decrease inototoxicity is computed relative to baseline measures prior to thepatient receiving a platinum based chemotherapeutic or sodiumthiosulfate or both.

The Brock scale is defined as follows: a ≤40 dB hearing loss at allfrequencies, which indicates a grade 0 or minimal hearing loss; a ≥40 dBhearing loss at 8,000 Hz only, which indicates a grade 1 or mild hearingloss; a ≥40 dB hearing loss at 4,000 Hz and above, which indicates agrade 2 or moderate hearing loss; a ≥40 dB hearing loss at 2,000 Hz andabove, which indicates a grade 3 or marked hearing loss; or a ≥40 dBhearing loss at 1,000 Hz and above, which indicates a grade 4 or severehearing loss.

The CTCAE scale is Based on hearing at 1, 2, 3, 4, 6, & 8 kHz. Grade 1is a threshold shift >20 dB at 8 kHZ in at least 1 ear; Grade 2 is athreshold shift >20 dB at 4 kHz and above in at least 1 ear; Grade 3 ishearing loss sufficient to indicate therapeutic intervention includinghearing aids, a threshold shift >20 dB at 3 kHz and above in at least 1ear; speech and language svcs indicated; and grade 4 is the audiologicindication of cochlear implant and speech and language svcs indicated.

The Children's Cancer Group 1996 scale is defined as follows: ≥40 dB HLloss at 6,000 and/or 8,000 Hz is indicative of grade 1, >25 dB HL lossat 3,000 and/or 4,000 Hz is indicative of grade 2, >25 dB HL loss at2,000 Hz is indicative of grade 3; and a ≥40 dB HL loss at 2,000 Hz isindicative of grade 4. Children's Hospital Boston scale is defined asfollows: <20 dB hearing loss at frequencies 500-8,000 Hz; no functionalhearing loss; >20 dB hearing loss above 4,000 Hz; functional loss:slight hearing loss that may result in decreased musical appreciationindicative of a grade 1; >20 dB hearing loss at 4,000 Hz and above;functional loss: educationally significant hearing loss indicative ofgrade 2; >20 dB hearing loss at 2,000 Hz and above; functional loss:severe hearing loss requiring hearing aids indicative of grade 3.

The Chang and Chinosornvatana scale is defined as <20 dB at 1, 2, and 4kHz is indicative of normal hearing; (1a) >40 dB at any frequency 6 to12 kHz; (1b) >20 and <40 dB at 4 kHz is indicative of grade 1a and 1b,respectively; (2a) ≥40 dB at 4 kHz and above; (2b) >20 and <40 dB at anyfrequency below 4 kHz is indicative of grade 2a and 2b, respectively;≥40 dB at 2 or 3 kHz and above is indicative of grade 3; and ≥40 dB at 1kHz and above is indicative of grade 4.

The American Speech-Language-Hearing Association criteria is defined as(1) ≥20 dB decrease at any one frequency; (2) ≥10 dB decrease at two ormore adjacent frequencies; or (3) loss of response at three adjacentfrequencies at which responses were previously obtained. The ASHAfurther specifies that a significant change in hearing sensitivity mustbe confirmed by repeat testing to be considered valid.

International Society of Pediatric Oncology Boston Ototoxicity Scale isdefined as ≤20 dB HL at all frequencies is indicated to be normalhearing; >20 dB HL (ie, 25 dB HL or greater); SNHL above 4,000 Hz (ie, 6or 8 kHz) is indicated to be grade 1; >20 dB HL SNHL at 4,000 Hz andabove is indicated to be grade 2; >20 dB HL SNHL at 2,000 Hz or 3,000 Hzand above is indicated to be grade 3; and >40 dB HL (i.e., 45 dB HL ormore) SNHL at 2,000 Hz is indicated to be grade 4.

The tinnitus functional index is a questionnaire-based index whichquantitates the severity of tinnitus symptoms (see Henry J A et al.,Audiology Today 26(6), pp. 40-48 (2014). The index is defined asfollows: a mean score of 14 (range of 0-17) is no tinnitus, a mean scoreof 21 indicates a low levels of tinnitus; a mean score of 42 is amoderate tinnitus; a mean score of 65 is high levels of tinnitus, and amean score of 78 is large levels of tinnitus. Ranges can be broken downinto <25 is relatively mild tinnitus or no tinnitus, 25-50 indicatessignificant problems with tinnitus, and >50 indicates levels of tinnitusthat require aggressive intervention.

In some embodiments, the ototoxicity is measured by measuring hearingloss at one or more frequencies comprising 500 Hz, 1,000 Hz, 2,000 Hz,4,000 Hz, or 8,000 Hz or a combination of frequencies thereof, wherein achange in hearing is computed relative to baseline measures prior to thepatient receiving a platinum based chemotherapeutic or sodiumthiosulfate or both. In some aspects, an increase in ototoxicity can bedetermined as a reduction in hearing measured by a 20 dB loss at asingle frequency; a reduction in hearing measured by a 10 dB loss at twoconsecutive frequencies; or a loss of response at three consecutive testfrequencies where responses were previously obtained. In some furtheraspects, an increase in ototoxicity is measured as a reduction inbilateral high-frequency hearing characterized by: a >40 dB hearing lossat all frequencies, which indicates a grade 0 or minimal hearing loss; a≥40 dB hearing loss at 8,000 Hz only, which indicates a grade 1 or mildhearing loss; a ≥40 dB hearing loss at 4,000 Hz and above, whichindicates a grade 2 or moderate hearing loss; a ≥40 dB hearing loss at2,000 Hz and above, which indicates a grade 3 or marked hearing loss; ora ≥40 dB hearing loss at 1,000 Hz and above, which indicates a grade 4or severe hearing loss. In still some further aspects, an increase inototoxicity is measured as a reduction in hearing characterized by: a≤20 dB hearing loss at all frequencies, which indicates a grade 0hearing loss; a >20 dB HL above 4,000 Hz, which indicates a grade 1hearing loss; a >20 dB HL at 4,000 Hz and above, which indicates a grade2 hearing loss; a >20 dB HL at 2,000 Hz or 3,000 Hz, which indicates agrade 3 hearing loss; or a >40 dB HL at 2,000 Hz and above, whichindicates a grade 4 hearing loss. In some other aspects, an increase inototoxicity can be measured by a reduction in a tinnitus functionalindex.

The administration of STS to pediatric patients being treated with aplatinum based chemotherapeutic was found to not exacerbate renal orother toxicities. Thus, in some aspects, patients receiving STS do notexperience more severe or an increased incidence rate of adverse eventscompared to patients not administered STS. These adverse events comprisegrade 3 or grade 4 neutropenia, reduced glomerular filtration rates,increased serum creatinine, infection, hypomagnesemia, hypernatremia,vomiting, or nausea. In some other aspects, pediatric patientsadministered STS do not have a reduction in relapse free survival oroverall survival compared to patients not administered STS.

The methods described herein are well suited for reducing or preventingototoxicity or reducing the likelihood of incurring ototoxicity in anypediatric patient of any age. Therefore, in some embodiments describedthe pediatric patient being treated following the methods describedherein may be a new born or the pediatric patient may about 1 month old,about 2 months old, about 3 months old, about 4 months old, about 5months old, about 6 months old, about 7 months old, about 8 months old,about 9 months old, about 10 months old, about 11 months old, about 12months old, about 1 year old, about 1.5 years old, about 2 years old,about 2.5 years old, about 3 years old, about 3.5 years old, about 4years old, about 4.5 years old, about 5 years old, about 5.5 years old,about 6 years old, about 6.5 years old, about 7 years old, about 7.5years old, about 8 years old, about 8.5 years old, about 9 years old,about 9.5 years old, about 10 years old, about 10.5 years old, about 11years old, about 11.5 years old, about 12 years old, about 12.5 yearsold, about 13 years old, about 13.5 years old, about 14 years old, about14.5 years old, about 15 years old, about 15.5 years old, about 16 yearsold, about 16.5 years old, about 17 years old, about 17.5 years old,about 18 years old, about 18.5 years old, about 19 years old, about 19.5years old, about 20 years old, about 20.5 years old, or about 21 yearsold. In some aspects, the pediatric patient is about 12 years of age orless, about 5 years of age or less, about 2 years of age or less, orabout 1 year of age or less.

It will be apparent to one of ordinary skill in the relevant art thatsuitable modifications and adaptations to the compositions,formulations, methods, processes, and applications described herein canbe made without departing from the scope of any embodiments or aspectsthereof. The compositions and methods provided are exemplary and are notintended to limit the scope of any of the specified embodiments. All ofthe various embodiments, aspects, and options disclosed herein can becombined in any and all variations or iterations. The scope of thecompositions, formulations, methods, and processes described hereininclude all actual or potential combinations of embodiments, aspects,options, examples, and preferences herein described. The exemplarycompositions and formulations described herein may omit any component,substitute any component disclosed herein, or include any componentdisclosed elsewhere herein. The ratios of the mass of any component ofany of the compositions or formulations disclosed herein to the mass ofany other component in the formulation or to the total mass of the othercomponents in the formulation are hereby disclosed as if they wereexpressly disclosed. Should the meaning of any terms in any of thepatents or publications incorporated by reference conflict with themeaning of the terms used in this disclosure, the meanings of the termsor phrases in this disclosure are controlling. Furthermore, theforegoing discussion discloses and describes merely exemplaryembodiments. All patents and publications cited herein are incorporatedby reference herein for the specific teachings thereof.

EXAMPLES Example 1 Study of Sodium Thiosulfate to Reduce Ototoxicity inPediatric Patients Recieving Cisplatin

The study was designed as a multicentre, randomised, open-label, phase 3clinical trial. Patients were enrolled at 38 participating Children'sOncology Group (COG) hospitals in the USA and Canada. Written consent orassent from participants or their legal guardians were obtained beforeregistration. The study was approved by the US National Cancer Institute(NCI) Central Institutional Review Board and site institutional reviewboards. Co-enrollment onto a companion observational cohort study ofototoxicity grading scales was mandatory. Participants in the study wereaged 1-18 years at study entry and were newly diagnosed withhepatoblastoma, germ cell tumour, medulloblastoma or CNS primitiveneuroectodermal tumour, neuroblastoma, osteosarcoma, or other cancertypes treated with cisplatin.

Key eligibility criteria included planned cumulative cisplatin dose of200 mg/m² or more and infusion duration of 6 h or less; performancescore of 50 or more by the Karnofsky (>16 years) or Lansky (≤16 years)scales; no previous cisplatin or carboplatin treatment; no known thiolhypersensitivity; and normal institutional laboratory values reflectinghaematological, renal, and hepatic function. Normal hearing was requiredbefore enrolment as defined by hearing thresholds of 20 dB hearing level(HL) or less at 500-8000 Hz when measured with earphones or 25 dB HL orless when measured in the sound field, or as defined by brainstemauditory evoked response thresholds equivalent to behavioural thresholdsof 20 dB HL or less. Previous cranial irradiation was initially notallowed but later permitted, provided hearing was normal, by a protocolamendment (Mar. 31, 2010) to augment trial recruitment. Patients werenot eligible if they were registered on a cancer directed COGtherapeutic study to avoid potential confounding of the primary aims bythe ACCL0431 randomization.

Patient Randomization

Patients were enrolled and randomly assigned to either the sodiumthiosulfate or observation (control group) up to 5 days before theyreceived any cisplatin. The allocation sequence for each stratumaccording to a permuted block algorithm was generated, where each blockof four contained two sodium thiosulfate and two control randomizations.The randomization was centrally computer-generated by the COG trialmanagement system. Allocation was electronically concealed to allinvestigators, clinicians, and participants. Site research staff did theenrolment, entering eligibility confirmation and specification ofstratification factors into the COG trial management system, andreceiving the electronically generated allocation for the site.Randomization was 1:1 and was initially stratified into four groupsdefined by age (<5 years or ≥5 years) and duration of cisplatin infusion(<2 h or ≥2 h). Later, we added one separate stratum for eligibleparticipants who had previously received cranial irradiation,irrespective of age or duration of cisplatin infusion. Randomization wasmasked for central reviewers of audiometry data, but was not placebocontrolled for participants or treating clinicians to minimisecomplexity and cost for participating sites.

Procedures

Cisplatin was administered as specified by each participant's cancertreatment plan. For participants randomly assigned to the control group,the cisplatin containing treatment regimen alone was to be administered.Participants in the sodium thiosulfate group received sodium thiosulfatedaily over 15 min beginning 6 h after the completion of each cisplatindose. The protocol specified sodium thiosulfate dose was 16 g/m² (533mg/kg where the cisplatin dose was calculated by bodyweight)administered as a 12.5% solution. This sodium thiosulfate dose wasselected because it was within the published effective dose range andwas well tolerated by children. For participants receiving multidaycisplatin regimens, a documented serum sodium concentration of less than145 mEq/L was required before each sodium thiosulfate dose, and aminimum of 10 h was to have elapsed between sodium thiosulfate and thenext cisplatin dose. Otherwise, no modifications of dose oradministration of sodium thiosulfate or other chemotherapy drugs weremade. Protocol guidelines for supportive care during the sodiumthiosulfate infusion included routine administration of antiemetics,limited blood pressure monitoring, and, if applicable, administration oflow-dose meperidine to manage infusion-related rigors. Concurrent use ofother ototoxic drugs (eg, aminoglycosides and loop diuretics) wasdiscouraged by protocol for all participants but captured in datareporting.

Cisplatin dose modifications were not captured as participants did notreceive cancer treatment according to specified protocols. Hearingassessments were done at baseline, up to 8 days before each cisplatincourse, 4 weeks after completion of the final cisplatin course, and 1year later. Audiometry included measurement of bilateral pure tone airconduction thresholds at 500-8000 Hz with earphones or in the soundfield using pediatric hearing assessment methods; otoscopy; immittanceevaluation of middle ear function; and evoked otoacoustic emissions, ifavailable. For participants unable to cooperate due to very young age,developmental disability, or medical status, brainstem auditory evokedresponse thresholds were to be measured instead.

Audiological testing was completed using standard clinical audiometers,middle ear analyzers, evoked potentials systems, and evoked otoacousticemission OAE systems (if available). All equipment was calibrated inaccordance with guidelines set forth by the AmericanSpeech-Language-Hearing Association. Audiological evaluations wasperformed at baseline (prior to the first dose of cisplatin), prior toeach cisplatin course, and both 4 weeks and 1 year after completion ofthe final course of cisplatin. Patients who proceeded to hematopoieticstem cell transplant following an Induction Phase that includescisplatin had audiological evaluations as above during the InductionPhase, 4 weeks after completion of the final cisplatin course duringInduction (i.e., pre-transplant) and both 4 weeks and 1 year posttransplant.

Audiological evaluations was conducted within 8 days and preferablywithin 72 hours, prior to each cisplatin infusion. Audiological testingincluded: (a) measurement of bilateral pure tone air conductionthresholds at 0.5-8 kHz; (b) otoscopy by audiologist or other healthcareprofessional; (c) immittance evaluation; and (d) measurement of evokedOAEs, if available. For patients too young to cooperate with standardaudiometric measurements, BAER should be obtained instead. Additionally,UHF audiometry will be performed for patients 5 years of age or older atinstitutions where that modality is available. Measurement of UHF willbe of bilateral pure tone air conduction thresholds at 9-16 kHz. Inaddition to institutional electronic entry of all required audiometrydata, a copy of each audiogram was faxed for independent review by twoexpert pediatric audiologists for whom randomization was masked (KK,BB); differences in interpretation were resolved by consensus. Hearingloss was determined according to American Speech-Language-HearingAssociation (ASHA) post hoc with a protocol-specific binaryclassification of localised versus disseminated.

Saliva or blood specimen were obtained from each participant who choseto assess mutations in the TPMT and COMT genes. Criteria for endingprotocol treatment included completion of the cancer treatment regimen,premature discontinuation of cisplatin, administration of cranialirradiation after enrolment but before measurement of the primaryendpoint, and inability to continue sodium thiosulfate. Participants offprotocol treatment were followed up for all endpoints. Criteria forremoval from the study included death, loss to follow-up, or entry ontoanother COG therapeutic study for the underlying cancer (in which casewe obtained survival data from that therapeutic study).

Outcomes

The primary endpoint was hearing loss at 4 weeks after final cisplatintreatment, but before any haemopoietic cell transplantation, accordingto validated ototoxicity criteria. Participants were deemed notassessable for this outcome if it was found during central review thataudiometry data derived from headphone, sound field, or brainstemauditory evoked response testing at baseline or post-treatment weremissing, incomplete, or technically unsatisfactory.

Secondary endpoints were frequency-specific hearing loss at 4 weeks (for500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, and 8000 Hz), haematological andrenal toxicity, event free survival (defined as the time from studyenrolment until disease relapse or progression, diagnosis of a secondmalignant neoplasm, or death, whichever came first), and overallsurvival (defined as the time from enrolment to death or last dateconfirmed alive). By protocol amendment on Mar. 31, 2010, we added anexploratory secondary aim to assess the association of mutations in theTPMT and COMT genes with cisplatin-induced hearing loss and sodiumthiosulfate effect.

Statistical Analysis

The primary endpoint of hearing loss according to ASHA criteria comparedthe audiometric evaluation at enrolment (ie, baseline) with the firstassessment done at least 4 weeks after the final dose of cisplatin (ie,posttreatment). Using a modified intention-to-treat approach, weanalysed patients on the basis of their randomization assignment,irrespective of treatment received, but included only eligibleparticipants who completed both baseline and post-treatment hearingassessments. The accrual goal was 108 participants with complete hearingevaluation allocated equally to the two study groups. We compared theproportion that developed hearing loss by treatment group using aone-sided χ² test. We deemed a p value of 0.05 or less to besignificant. Assuming a 4-week cumulative hearing loss incidence of 45%in the control group and an incidence of 22.5% in the sodium thiosulfategroup, the study as designed would provide 80% power. The probability ofhearing loss among patients in the control group was based on acontemporary pediatric report involving multiple tumour types. Reductionof this probability by half was deemed clinically relevant. Becauseparticipants who had received previous cranial irradiation were addedthrough an amendment, we did a post-hoc sensitivity analysis thatincluded only participants who were not enrolled in the new stratum. Wealso did a post-hoc analysis of hearing loss at the 1-year timepoint forparticipants who had interpretable audiometry data and had not had asurvival event or haemopoietic cell transplantation; these participantswere excluded due to the inability to control for additional ototoxicexposures.

We estimated the magnitude of the association between sodium thiosulfateassignment and hearing loss using the odds ratio (OR); p values for thetest of OR=1 and corresponding 95% CI were derived using the Wald testfor the parameter associated with the randomised treatment assignmentfrom a logistic model. The logistic model was stratified according tothe strata used for randomization. We estimated stratum-specificprobabilities of hearing loss using the observed proportion ofassessable participants in the particular stratum with hearing loss; wealso calculated exact 95% CIs.

We planned interim monitoring for futility of an otoprotective effect ofsodium thiosulfate. After we ascertained the primary outcome measure inthe first 60 patients, we calculated the probability of rejecting thenull hypothesis at the end of planned enrolment on the basis of observedhearing loss to that point and the assumption that development ofhearing loss for future participants would follow the alternativehypothesis. If this conditional probability was 0.10 or less, the studywas to be identified to the COG Data and Safety Monitoring Committee forclosure due to lack of efficacy.

The change in hearing threshold between baseline and post-treatmenttimepoint at different frequencies (500 Hz, 1000 Hz, 2000 Hz, 4000 Hz,and 8000 Hz) was determined by the mean change, and assessed thehypothesis of no difference between groups using the Wilcoxon two-sampletest for non-parametric data. We deemed a one-sided p value 0.05 or lessto be significant; we made no adjustment for multiple comparisons forthis assessment.

For haematological and renal toxicity, denominators represent the numberof participants who completed the required toxicity assessment duringeach cycle. For both types of toxicity, we assessed the hypothesis of nodifference in incidence using a x² test of proportions.

For event-free survival and overall survival, patients who did not havean event were censored at time of last contact. We estimated theprobability of remaining event free as a function of time post-enrolmentusing the method of Kaplan and Meier. We compared risk of event acrossgroups defined by randomised regimen using the log-rank statistic. Wegenerated relative hazard ratios (RHR) and 95% CIs by fitting arelative-risk regression model, using partial likelihood where the modelcontained the characteristic of interest as the only variable. Wecomputed survival estimates as 3-year event-free survival and 3-yearoverall survival. We did a post-hoc analysis of event-free survival andoverall survival by extent of disease using the same methods. Weconsidered all eligible participants in the survival analyses byintention to treat. We did all statistical calculations using SAS(version 9.4) or Stata (version 14).

Results

Between Jun. 23, 2008, and Sep. 28, 2012, 131 participants from 38institutions were enrolled in the study, reaching the planned accrualgoal (see scheme FIG. 1). Six participants were deemed ineligible; fourbecause they were co-enrolled on a disease directed COG therapeuticstudy (with three participants randomly assigned to sodium thiosulfateand one to control), one because cranial irradiation was administeredbefore reaching the primary endpoint (randomly assigned to control), andone because there was no source documentation of normal baseline serumelectrolyte values (randomly assigned to sodium thiosulfate). Of the 125eligible participants, 38 were enrolled before and 87 after the protocolamendment that allowed participants who had previously received cranialirradiation to enrol (n=9). 64 participants were randomly assigned tothe control group and 61 to the sodium thiosulfate group. Interimmonitoring resulted in recommendations to continue the trial as planned.Data current to Mar. 31, 2015, were used in this analysis.

Baseline characteristics were similar between treatment groups. Theoverall proportions of eligible participants with disseminated diseaseat study entry were similar; four eligible participants in each grouphad previously received cranial irradiation. The disease-specificcharacteristics of participants by randomization group with respect toage and extent of disease were balanced between groups. The mediancumulative cisplatin dose for the control group was 387 mg/m² (IQR305-466) and for the sodium thiosulfate group was 393 mg/m² (290-420).The median cumulative sodium thiosulfate dose was 95.8 g/m²(60.1-127.6). The proportions of participants who had received loopdiuretics or aminoglycoside antibiotics were similar in the control (17[27%] of 64 participants) and sodium thiosulfate (17 [28%] of 61participants) groups. No participants underwent haemopoietic celltransplantation before assessment for the primary endpoint.

104 participants were assessable for post-treatment hearing loss at 4weeks (55 of 64 participants in the control group and 49 of 61 in thesodium thiosulfate group). Of these assessable participants, 14 (29%) inthe sodium thiosulfate group and 15 (27%) in the control group wereyounger than 5 years. Hearing loss was identified in 14 (28.6%; 95% CI16.6-43.3) participants in the sodium thiosulfate group compared with 31(56.4%; 42.3-69.7) in the control group (p=0.00022).

For participants younger than 5 years, the incidence of hearing loss wasunexpectedly and substantially lower in the sodium thiosulfate groupthan in the control group (three [21.4%] of 14 participants [95% CI4.7-50.8] vs 11 [73.3%] of 15 [44.9-92.2]); whereas the difference inincidence between groups was not as large for older patients (11 [31.4%;16.9-49.3] of 35 vs 20 [50.0%; 33.8-66.2] of 40). The incidence ofhearing loss was lower for participants in the sodium thiosulfate groupthan in the control group after cisplatin infusion of 2-6 h (ten [41.7%;95% CI 22.1-63.4] of 24 vs 21 [70.0%; 50.6-85.2] of 30) and aftercisplatin infusion of less than 2 h (four [16.0%; 4.5-36.1] of 25 vs ten[40.0%; 21.1-61.3] of 25). The stratum of previous cranial irradiationcontained only eight assessable participants; hearing loss occurred intwo (50%) of four sodium thiosulfate-treated participants versus four(100%) of four patients in the control group. When these eightirradiated participants were excluded in a post-hoc analysis, hearingloss was noted in 12 (26.7%; 95% CI 14.6-41.9) of 45 participants in thesodium thiosulfate group compared with 27 (52.9%; 38.5-67.1) of 51 inthe control group (p=0.0045). By the logistic test adjusted forstratification variables, the likelihood of hearing loss wassignificantly lower in the sodium thiosulfate group compared with thecontrol group (OR 0.31, 95% CI 0.13-0.73; p=0.0036). When the eightirradiated participants were removed from the analysis, the unadjustedOR was 0.32 (95% CI 0.13-0.76; p=0.010). Of the 104 participantsassessable for hearing loss at the primary endpoint, 67 were alsoassessable at 1 year in a post-hoc analysis; of these, nine (28%) of 32participants who received sodium thiosulfate had ASHA-defi ned hearingloss compared with 19 (54%) of 35 controls (p=0.0015). For the eightassessable participants who had previously received cranial irradiation,none of their hearing outcomes at 1 year were changed from the 4-weektimepoint.

The mean change in hearing threshold within key frequencies is shown inthe table below. For the sodium thiosulfate group, the change in hearingthreshold from baseline to 4 weeks after cisplatin treatment was smallerthan in the control group, although there was no significant differencebetween the groups.

Mean change in hearing threshold within key frequencies Change ControlSTS between Hz Mean (SD) n Mean (SD) n p-value groups 500 −1.1 (8.6)  45−1.5 (5.8) 38 0.34 0.4 1000 −0.3 (9)    47 −0.7 (4.6) 37 0.36 0.4 20000.6 (12.7) 47 −1.2 (4.9) 38 0.42 1.8 4000 9.6 (20.5) 47   1.1 (7.1) 380.11 8.5 8000 17.0 (24.7)  42   9.7 (17.3) 37 0.18 7.3 *A negative valueindicates a better mean hearing threshold compared with the baselineevaluation and a positive value indicates a poorer mean hearingthreshold.

Haematological toxicity was not significantly different between thetreatment groups, occurring in 137 (77%) of 177 participant cycles inthe sodium thiosulfate group and 172 (77%) of 223 participant cycles inthe control group (p=0.95). Aggregate nephrotoxicity was more common inthe sodium thiosulfate group, in which 37 (25%) of 147 participantcycles were affected versus 25 (13%) of 187 controls (p=0.0059).Hypophosphataemia and hypokalaemia were more common in the sodiumthiosulfate group than in the control group. Notably, no cases of eitherincreased creatinine or reduced glomerular filtration rate met the CTCAEgrade 3 threshold in either group.

The most common grade 3-4 haematological adverse events, irrespective ofattribution, were neutropenia (117 [66%] of 177 participant cycles inthe sodium thiosulfate group vs 145 [65%] of 223 in the control group),whereas the most common non-haematological adverse event washypokalaemia (25 [17%] of 147 vs 22 [12%] of 187). As part of the NCIAdverse Event Reporting System, this study included expedited reportingof serious adverse events. Reporting was required only for participantsrandomly assigned to the sodium thiosulfate group. 194 serious adverseevents were reported in 26 patients; of these, 112 were deemedunrelated, 62 unlikely, 20 possibly, and none probably or definitelyrelated to sodium thiosulfate. 85 were non-haematological adverseevents, of which 49 were deemed unrelated, 25 unlikely, 11 possibly, andnone probably or definitely related to sodium thiosulfate; 70 werehaematological adverse events, of which 53 were deemed unrelated, 13were deemed unlikely, four possibly, and none probably or definitelyrelated to sodium thiosulfate. Of the 194 serious adverse events, thethree most common were decreased neutrophil count (26 [13%] in 14participants), decreased platelet count (23 [12%] in 12 participants),and anaemia (21 [11%] in ten participants).

All 125 eligible patients were included in the analysis of event-freesurvival and overall survival. Median follow-up was 3.5 years (IQR1.4-4.5) for event-free survival (median follow-up 3.4 years [IQR2.9-4.3] for the sodium thiosulfate group, and 3.8 years [3.1-4.5] forthe control group) and 3.5 years (1.5-4.5) for overall survival (medianfollow-up 3.4 years [2.9-4.3] for the sodium thiosulfate group, and 3.8years [3.1-4.7] for the control group). Among the 61 participantsassigned to sodium thiosulfate, 26 events and 17 deaths occurred; amongthe 64 participants in the control group, 24 events and ten deathsoccurred. All events were relapse except for one participant in thesodium thiosulfate group who developed a second malignant neoplasm. Asclassified by site investigators, all deaths were deemed to be due todisease, except for one death in the sodium thiosulfate group that wasattributed to cancer treatment-related sepsis but was not related tosodium thiosulfate. Considering the entire sample, no significantdifference was noted between the sodium thiosulfate and control groupsfor event-free survival or overall survival (FIG. 2). 3-year event-freesurvival was 54% (95% CI 40-66) in the sodium thiosulfate group versus64% (50-74) in the control group; 3-year overall survival was 70%(56-80) versus 87% (76-93).

Because of the possibility of an effect of sodium thiosulfate onsurvival that emerged for the sample as a whole, we did a post-hocstratification of the sample by extent of disease at enrollment. Withinthe group deemed to have localised disease (n=77), we found nosignificant difference between treatment groups in event-free survival(median follow-up 3.4 years [IQR 3.2-4.3] for the sodium thiosulfategroup, and 3.7 years [3.1-4.5] for the control group) or overallsurvival (median follow-up 3.5 years [3.2-4.3] for the sodiumthiosulfate group, and 3.8 years [3.0-4.8] for the control group; FIG.3). The 3-year event-free survival was 60% (95% CI 42-74) for the sodiumthiosulfate group versus 66% (48-78) for the control group; 3-yearoverall survival was 83% (66-92) versus 89% (74-96). Among participantswith localised disease, 14 events and six deaths in both the control andsodium thiosulfate groups occurred. Among participants deemed to havedisseminated disease (n=47), we found no difference between treatmentgroups in event-free survival (median follow-up 3.2 years [IQR 3.0-4.3]for the sodium thiosulfate group, and 4.1 years [3.1-4.5] for thecontrol group), but overall survival was significantly lower in thesodium thiosulfate group compared with the control group (medianfollow-up 3.2 years [3.0-4.5] for the sodium thiosulfate group, and 3.8years [3.1-4.5] for the control group; FIG. 3). 3-year event-freesurvival was 42% (95% CI 21-61) in the sodium thiosulfate group versus61% (39-77) in the control group; 3-year overall survival was 45%(23-65) versus 84% (62-94). In participants with disseminated disease,12 events and 11 deaths occurred in the sodium thiosulfate group and tenevents and four deaths occurred in the control group. Study data showingpatient demographics, hearing loss in both treatment arms, andKaplan-Meier survival curves for the entire study in addition to resultsstratified by cancer subtype and patient age may be found in (FIGS.2-35).

Example 2: Sodium Thiosulfate (STS) as an Otoprotectant to Reduce theIncidence of Cisplatin-Induced Hearing Loss for Standard RiskHepatoblastoma

The study was designed as a multi-centre open label randomised phase IIItrial to test the efficacy of Sodium Thiosulphate (STS) in reducingototoxicity in patients receiving Cisplatin chemotherapy for standardrisk hepatoblastoma. A total of 52 centers participated in 11 countriesworldwide including United Kingdom, France, Belgium, Japan, Italy,Spain, Australia, New Zealand, Ireland, Switzerland, and the UnitedStates. The control arm included cisplatin only treated patients and thetest arm including cisplatin treated patients followed by administrationof STS.

End-Points

The primary end point of the study was the rate of Brock grade ≥1hearing loss determined after end of trial treatment or at an age of atleast 3.5 years, whichever was later. Secondary end-points included:response to preoperative chemotherapy, complete resection, completeremission, event free survival (EFS), overall survival (OS), toxicity asgraded by CTCAE v 3.0, long-term renal clearance, and feasibility ofcentral audiology review

Patient Inclusion Criteria

Patients were included in the study if they had a histologicallyconfirmed newly diagnosed hepatoblastoma according to the followingcriteria:

-   -   Standard risk hepatoblastoma:        -   Pre-treatment Tumour Extension (PRETEXT) I, II or III (see            Pretext table below)        -   Serum alpha-fetoprotein (AFP) >100 μg/L        -   No additional PRETEXT criteria

No of patients with a complete No. patients No. of No of tumour who diedof patients No. of positive resection incl surgical who died OS at 3patients responses (%) OLT (%) complications of disease years Standardrisk 77 69 (90%) 75 (97%) 2 (3%) 5 (6%) 91% PRETEXT I 6  6 (100%)  6(100%) — — 100%  II 39 37 (95%) 39 (100%) 1 (3%) 1 (3%) 95% III 32 26(81%) 30 (94%) 1 (3%) 4 (13%) 84%

-   -   Age ≤18 years and >1 month    -   Written informed consent and national/local ethics committee and        regulatory approval    -   Centre/country willing and able to organize audiometry at        minimum required quality standard    -   Ability to comply with requirements for submission of material        for central review (radiology, pathology and audiology)    -   For females of child-bearing potential, a negative pregnancy        test prior to study treatment was required    -   Any patient who was of reproductive age had to agree to use        adequate contraception for the duration of the trial (males had        to always use a condom and females had to ensure their partner        used a condom, and used one additional method of contraception        for the duration of the period of chemotherapy)

Patient Exclusion Criteria

Patients were excluded from the study if they met any of the followingexclusion criteria:

-   -   High risk hepatoblastoma:    -   Serum—Alpha-fetoprotein (AFP)≤100 μg/L    -   Tumour involving all 4 hepatic sections—PRETEXT IV    -   Additional PRETEXT criteria        -   Extrahepatic abdominal disease (E1, E1a, E2, E2a)        -   Intraperitoneal haemorrhage or tumour rupture (H1)        -   Distant metastases, any site (M1)        -   Lymph node metastases (N1, N2)        -   Involvement of the main portal vein (P2, P2a)        -   Involvement of all three hepatic veins and/or the IVC (V3,            V3a)    -   Hepatocellular carcinoma    -   Treatment starting more than 15 days from written biopsy report    -   Abnormal renal function defined as calculated GFR <75% of the        lower limit of normal for age at diagnosis, which over 2 years        of age is <60 ml/min/1.73 m²    -   Any previous chemotherapy    -   Recurrent disease    -   Previous hypersensitivity to STS    -   Patient unable to follow the protocol for any reason

Randomization

Patients that met the above eligibility criteria were enrolled andrandomly assigned to either the Sodium Thiosulfate or observation(control group) prior to receiving Cisplatin. The randomization andpatient enrollment diagrams are provided in FIGS. 36 and 37. Theenrolled patient characteristics were provided in FIG. 38.

Trial Treatment

The Investigational Medicinal Products (IMPs) studied in this trial wereSodium Thiosulphate (STS) and Cisplatin. STS was provided by AdherexTechnologies. Trial treatment consisted of the following phases:

-   -   Pre-operative randomised 1:1 chemotherapy (4 courses of        Cisplatin, with or without STS, every second week)    -   Surgical removal of all remaining tumour lesions. If surgery has        to be delayed, 1 or 2 cycles of the post-operative chemotherapy        may be given pre-operatively.    -   Post-operative chemotherapy (2 courses of Cisplatin, with or        without STS, every second week)    -   Patients with progressive disease after 2 or more courses of        Cisplatin, with or without STS, discontinued trial treatment

Treatment and Follow-Up Plan

-   -   Pre-operative chemotherapy, 4 courses Cisplatin+/−STS    -   Definitive surgery after pre-operative chemotherapy (as in all        previous SIOPEL trials)    -   Post-operative chemotherapy, 2 courses Cisplatin+/−STS (this can        be given pre-operatively if surgery has to be delayed for valid        practical reasons)    -   Long-term follow-up

Treatment Failure

-   -   Treatment was stopped in patients with progressive disease after        2 or more courses of Cisplatin with or without STS    -   No further STS    -   2-4 courses Cisplatin-Doxorubicin (PLADO) were recommended,        followed by definitive surgery when the response was sufficient    -   Ideally 2 courses

Chemotherapy Guidelines and Administered Treatments

Cisplatin

Cisplatin was supplied in 10 ml, 50 ml and 100 ml vials containing a 1mg/ml solution formulations and optionally as a powder forreconstitution in 50 mg vials. Stability of the Cisplatin formulationfollowed the following:

-   -   Pre dilution: as per manufacturer's Summary of Product        Characteristics    -   Post dilution: Cisplatin could be stable for up to a maximum of        7 days in a solution of sodium chloride. The manufacturer's        Summary of Product Characteristics was followed.

Sodium Thiosulphate (STS) Source and Pharmacology

STS is a water-soluble thiol compound with reducing agent properties.Following IV injection, sodium thiosulphate was distributed throughoutthe extracellular fluid. Some Sodium Thiosulphate was converted tosulphate in the liver. Up to 95% was excreted unchanged in the urine.The biological half-life was 0.65 hours (range: dependent on dose16.5-182 minutes).

Packaging and Labelling

Each vial was placed into a six vial kit box. Each box was labelled witha multi-language kit label. STS drug product was manufactured, labelled,and packaged under GMP conditions and supplied as a 25% (250 mg/mL),preservative free, sterile solution. The drug product formulationcontained sodium thiosulfate pentahydrate and sodium borate. The viallabel indicated the drug product batch number and the initial releaseuntil date.

Preparation

STS was supplied in 50 ml vials containing a 25% (250 mg/ml or 12.5g/vial) solution. Each ml of the 25% STS was diluted with one ml ofsterile water for injection (1:1 dilution) to a concentration of 125mg/ml for direct administration. (This is approximately equivalentisotonicity to a 2.3% sodium chloride solution). The volume from theappropriate number of vials for the dose was combined in a PVC IVinfusion bag.

Reconstituted STS for administration consisted of a clear solution.There were no preservatives in the formulation. After dilution the PVCinfusion bag containing the dosing solution was placed upside down(inverted with injection and filling ports at the top) at roomtemperature and used within eight hours. Any solution remaining in thevial was destroyed according to institutional procedures.

Treatment Schedule

For all patients, the pre-surgery courses were given on day 1, 15, 29and 43 (exceptionally, if surgery was delayed, courses could also begiven on day 57 and 71). Post-surgery courses were started as soon aspossible, but within 21 days with two courses given on day 1 and 15.Prior to starting each cycle of chemotherapy, the following measurementswere established: whether the child had a good urine output, serumelectrolytes and creatinine within the normal range for age and stableblood pressure <97^(th) percentile for age, normal neurology and whetherthe child was febrile. The following treatment schedules were followed:

Cisplatin

For children >10 kg: 80 mg/m² IV infusion over 6 hours For infants andchildren 5-10 kg: 2.7 mg/kg IV infusion over 6 hours For infants <5 kg:1.8 mg/kg IV infusion over 6 hours

Sodium Thiosulphate

For children randomised to receive STS:

For children >10 kg: 20 g/m² IV infusion over 15 minutes For infants andchildren 5-10 kg: 15 g/m² IV infusion over 15 minutes For infants <5 kg:10 g/m² IV infusion over 15 minutes

Administration

Pre-Hydration

-   -   At least 3 hours pre-hydration with 2.5% dextrose/0.45% saline    -   Run at 200 ml/m2/hr (total volume 600 ml/m²)

Cisplatin Infusion Over 6 Hours

-   -   Cisplatin in 0.9% sodium chloride. Suggested volume for infusion        over 6 hours:    -   <60 mg in 60 ml, 60 mg-120 mg in 120 ml and >120 mg in 240 ml    -   No fluids other than sodium chloride were used as a vehicle for        Cisplatin in order to prevent chloride depletion, which would        lead to increased risk for nephrotoxicity.

Hydration During and Until 6 Hours Post Cisplatin (i.e. 12 Hours inTotal)

-   -   2.5% Dextrose/0.45% Sodium Chloride    -   Plus 6 g mannitol per 500 ml    -   Plus 10 mmol potassium chloride per 500 ml    -   Run at 125 ml/m2/hr

Sodium Thiosulphate 6 Hours Post Cisplatin

-   -   Diluted each ml of the 25% STS with 1 ml of sterile water for        injection (1:1 dilution) to a concentration of 125 mg/ml for        direct administration. (This has an approximately equivalent        iotonicity to a 2.3% sodium chloride solution)    -   Infused over 15 minutes    -   Stopped the Cisplatin hydration fluid for 15 minutes during the        STS infusion. Restarted the Cisplatin hydration immediately        afterwards

Hydration for Subsequent 18 Hours (i.e. Until 24 Hours after the End ofCisplatin Infusion)

-   -   2.5% Dextrose/0.45% sodium chloride    -   Plus 10 mmol potassium chloride per 500 ml    -   Plus 5 mmol magnesium sulphate per 500 ml    -   Plus 0.3 mmol calcium gluconate per 500 ml    -   Run at 125 ml/m2/hr

SUMMARY

-   -   −3 hr start pre-hydration    -   0 hr finish pre-hydration, start Cisplatin infusion+hydration        over 6 hours    -   6 hr finish Cisplatin infusion, continue with hydration for a        further 6 hours    -   12 hr finish hydration, start STS infusion    -   12 hr 15 min finish STS infusion, start post hydration    -   30 hr 15 min finish post hydration

A Bedside Nursing Work Sheet was provided to assist with the timings ofCisplatin, Sodium Thiosulphate (STS), hydration and anti-emeticadministration. The worksheet was adapted to suit local practice. Papercopies of the worksheet were kept in the child's notes ready to befilled in when chemotherapy was given. The worksheet also included atable to record blood pressure and electrolyte monitoring for patientsreceiving STS.

Toxicity Monitoring

The trial treatment was recognized to be potentially toxic and childrenwere at risk of developing myelo-, mucosal- or other reversible toxicityas well as irreversible oto- and renal toxicity. Therefore, toxicitymonitoring was required for each child throughout trial treatment and atregular follow-up intervals. The reporting of specific renal andoto-toxicity was required as an adverse event. Serious Adverse Eventswas reported immediately on knowledge of the event. The trial committeeevaluated toxicity reports on a regular basis and was authorized to stopthe trial if an unacceptable rate of severe toxicity was recognized. Thedose and treatment modifications due to toxicity were specified in theprotocol. In addition, long-term follow up of patients in this trialwere to include any late toxicity. The occurrence of adverse events isshown in FIG. 39.

Adverse drug reactions were monitored and defined as adverse events,which are possibly, probably or definitely related to the trialtreatment and were assessed according to NCI CTCAE v 3.0. A SeriousAdverse Event was defined—in accordance with the ICH HarmonisedTripartite Guideline for Good Clinical Practice definitions andadditionally—as any untoward medical occurrence that: results in death(NB: death by tumour progression is not considered an SAE for thesepatients). A serious adverse event is one that is life-threatening,requires inpatient hospitalization or prolongation of existinghospitalization, leads to progression of disease, is an overdosage, is asecond primary malignancy, results in persistent or significantdisability/incapacity, is a congenital anomaly, any unexpected grade 3and 4 toxicity

Definition of Study Completion

The primary endpoint was reached when the last patient completed his/heraudiological testing or reached 3.5 years of age, whichever was later.Patients were then followed up for the secondary endpoints according tonational guidelines

Audiometry

This trial was aimed at reducing ototoxicity in very young patients withhepatoblastoma. In order not to have to refuse patients entry into thetrial, the end point only required pure tone audiometry to be carriedout at the age of 3.5 years when the child is off treatment. In somecases this meant that the child moved to another centre to be tested.

In order to make central review meaningful all audiologic evaluationswere completed using standard clinical audiometers, middle earanalyzers, and evoked Otoacoustic Emission (OAE) systems. All equipmentwas calibrated in accordance with international guidelines. Baselinehearing evaluations were completed before the first dose of Cisplatinwhenever possible. Definitive audiologic evaluation was completed forall children at the age of 3.5 years (or as soon as a reliable hearingtest could be obtained). The minimum criteria for entry into this trialwas that Pure Tone Audiometry could be completed, together with otoscopyand tympanometry, at the end of treatment directly or when the childreached the age of 3.5 years, if younger at the end of treatment. Theaudiological testing was required to take place in a competentdepartment familiar with testing young children. The parents agreed inwriting, on the trial consent form, to travel to a centre, in anothertown in their country, if necessary, in order to get this done. The endof treatment audiological review was then provided for central review.All participating centres were asked to give contact details of theConsultant Audiologist or Ear Nose and Throat Surgeon who wasresponsible for coordinating and overseeing the quality of the centreconsidered competent to carry out this end of treatment audiologicalassessment in their country.

Audiologic evaluations included: Measurement of bilateral pure tone airconduction thresholds at 8, 6, 4, 2, 1 and 0.5 kHz starting with thehigh frequencies, otoscopy, Immittance evaluation or tympanometry,measurement of TEOAEs and DPOAEs at facilities where this equipment wasavailable. If a child was uncooperative or too unwell to give reliableresponses on behavioural assessment and had middle ear effusion andhence TEOAE and DPOAE could not be done then thresholds were obtainedusing bone conduction auditory brainstem response (ABR). Ideally usingtone burst, but click evoked ABR would also be helpful

Procedures for obtaining pure tone thresholds included standardbehavioural measurement techniques appropriate for the age anddevelopment of the child, including conditioned play audiometry andvisual reinforcement audiometry. During the study, a descending testingprocedure, starting at 8000 Hz, was recommended for all children and wasespecially important for children with limited cooperation, as anydecrease in auditory sensitivity will most likely occur at the higherfrequencies. Obtaining 0.5 kHz was recommended as tester could reassessreliability of responses. Inserted earphones or headphones were used toobtain ear-specific thresholds whenever possible. Bone conductionthresholds were measured if baseline testing indicated pre-existinghearing loss, if a child had a significant decrease in hearing at thedefinitive evaluation, and/or if immittance results indicated conductivemiddle ear pathology. When behavioural test results could not bereliably obtained, auditory thresholds were estimated using anelectrophysiologic test procedure, specifically click or tone burstevoked ABR.

Immittance evaluation included the measurement of middle ear pressureand compliance and acoustic reflex thresholds. Probe tones were equal toor greater than 660 Hz instead of 226 Hz in babies. Tympanograms wereclassified as normal if the static admittance is 0.2 mmho or greater,the peak pressure between −150 to +200 daPa, and the tympanometric widthless than 160 daPa. Acoustic reflex thresholds were measured at 500,1000, 2000 and 4000 Hz ipsilaterally in both ears.

Transient Evoked Otoacoustic Emissions (TEOAEs) and Distortion ProductOtoacoustic Emissions (DPOAE)s were collected at facilities when theequipment was available. If a child exhibited evidence of active middleear disease, as evidenced by abnormal tympanometry and/or conductivehearing loss, Otoacoustic Emission (OAE) measurement was deferred untilthe middle ear pathology resolved. For TEOAEs click stimuli waspresented at 80 dB peak equivalent SPL. The two TEOAE parameters thatwere used to compare results was total emissions level (mean response)and the reproducibility of the waveforms in the frequency region1000-4000 Hz. For DPOAEs one level of L1 and L2 65/55 dB SPL was done atleast at four frequencies. TEOAE is regarded as a better predictor oflow frequency and DPOAE of high frequency sensitivity.

The following test protocols were used based upon the age of thepediatric patient: Evaluation for children younger than 12 months of ageincluded: Measurement of minimal thresholds by visual reinforcementaudiometry (VRA) preferably with insert ear phone, if the child did notaccept that, then on sound field setting with dBA weighting wasconverted to equivalent of hearing level (HL) by the central audiologycommittee through the to equate to pure tones. In addition,tympanometry, and the measurement of TEOAEs and DPOAEs was carried out.Click or tone burst evoked ABRs were used to estimate auditorythresholds if possible. If ABR was not available, acoustic reflexthresholds was measured.

Evaluation for children younger than 12-42 months of age included:Evaluation by VRA or conditioned play audiometry, if thresholds wereestimated on sound field setting in dBA weighting was converted to HL.In addition, tympanometry, and the measurement of TEOAEs and DPOAEs wascarried out. Click or tone burst evoked ABRs were used to estimateauditory thresholds if possible. If ABR was not available, acousticreflex thresholds was measured. If reliable results could not beobtained by behavioural testing, then ABR or acoustic reflex thresholdmeasurement was recommended.

Evaluation for children 3.5 years and older included: Evaluation usingplay audiometry as described above or standard pure tone threshold.addition, tympanometry, and the measurement of TEOAEs and DPOAEs wascarried out.

Guidelines for visual reinforcement audiometry (VRA) included visualreinforcement audiometry is the standard accepted method for obtainingfrequency and ear specific hearing thresholds in children between theages of 6 months through 30 months. Animated and/or lighted toys areused to condition and reinforce a head-turning response to sound. Insertearphones should be used whenever possible. If a child will not toleratewearing earphones, testing may be completed using warbled pure tonepresented through calibrated sound field speakers. These thresholdsmeasured as dBA should be converted to dB HL for purpose of this study.

Guidelines for auditory brainstem response (ABR) included testing forair conduction (AC) threshold estimation is difficult in very youngchildren who will not cooperate for behavioural assessment or for OAEs.Measurement of auditory evoked brainstem potentials is anelectrophysiologic procedure, which allows for evaluation of peripheralauditory function and threshold determination in subjects who are notable to participate in behavioural testing due to cooperation or stateof health. Although ABR does not measure hearing sensitivity, ABRthresholds are strongly correlated with thresholds of hearingsensitivity and allow for an estimation of auditory thresholds.

Frequency specific tone burst stimuli were used to measure ABRthresholds whenever possible for 500, 1000, 2000, and 4000 Hz stimuli.Thresholds for click stimuli were obtained if evaluation with frequencyspecific stimuli is not available. ABR thresholds will be determined asthe lowest level at which detectable, repeatable wave V responses areobtained. Responses were labelled only when replicable and compared withnormative pediatric data. Frequency specific stimulus, i.e. tone burstlow, mid and high frequency or click evoked ABR, is delivered viaearphones. If the AC thresholds were raised, i.e. greater than 20 dB nHLor where due to time constraints it is not possible to do fullaudiological evaluation, then bone conduction (BC) testing was carriedout to determine the thresholds of the better hearing ear. Thresholdsshould be determined using 10 dB steps down to 20 dB nHL. All thresholdsobtained in dB nHL were converted to HL using the conversion table.

Guidelines for OAE

Otoacoustic emissions are sounds that are produced by healthy ears inresponse to acoustic stimulation. They are byproducts of the activity ofthe outer hair cells in the cochlea. OAEs are measured by presenting aseries of very brief acoustic stimuli, clicks, to the ear through aprobe that is inserted in the outer third of the ear canal. The probecontains a loudspeaker that generates clicks and a microphone thatmeasures the resulting OAEs that are produced in the cochlea and arethen reflected back through the middle ear into the outer ear canal. Theresulting sound that is picked up by the microphone is digitized andprocessed by specially designed hardware and software. The verylow-level OAEs are separated by the software from both the backgroundnoise and from the contamination of the evoking clicks.

Monitoring During Treatment

After the initial baseline audiologic evaluation as recommended beforestart of treatment, interim audiometry was recommended after everysecond cycle of Cisplatin. In children younger than 3.5 years of ageinterim audiometry was strongly recommended.

All children had a definitive evaluation when they completed treatmentand were aged 3.5 years or older. If the child was old enough theevaluation was done within 6-12 weeks after the last Cisplatin dose.Ototoxicity was assessed using Brock grading as defined herein, as wellas ASHA guidelines wherever pre-chemotherapy hearing thresholds wereavailable. If the children had hearing loss equal to or greater thanBrock's grade 1 on the definitive audiologic evaluation, that wasconsidered as positive for ototoxicity.

Wherever ASHA criteria could be applied, ototoxicity was defined aspositive when there is a hearing loss of: 20 db decrease at any one testfrequency or 10 db decrease at any two adjacent frequencies or loss ofresponse at three consecutive test frequencies where responses werepreviously obtained (this refers to high frequencies) as described byASHA criteria. In cases of asymmetric hearing loss, results will bereported for both ears.

All audiologic data was centrally reviewed. The data was collected oneach child and was submitted in HL weighting. Data was submitted forcentral review as soon as possible after the tests have been performed.ASHA criteria and OAE guidelines and Brock grading guidelines followedin this study are described below.

Brock Grading and ASHA Criteria

Brock Grading

The Brock grading system was used to monitor Cisplatin-induced bilateralhigh-frequency hearing loss (grades 1-4)

BILATERAL HEARING LOSS GRADE Designation <40 dB at all frequencies 0Minimal ≥40 dB at 8,000 Hz only 1 Mild ≥40 dB at 4,000 Hz and above 2Moderate ≥40 dB at 2,000 Hz and above 3 Marked ≥40 dB at 1,000 Hz andabove 4 Severe

ASHA Criteria and Guidelines:

From the American Speech-Language-Hearing Association Guidelines for theaudiologic management of individuals receiving cochleotoxic drug therapyand Guidelines for the audiologic assessment of children from birth to 5years of age.

Elements of Monitoring:

The cochleotoxicity monitoring programme at study locations required (a)specific criteria for identification of toxicity, (b) timelyidentification of at-risk patients, (c) pre-treatment counsellingregarding potential cochleotoxic effects, (d) valid baseline measures(pre-treatment or early in treatment), (e) monitoring evaluations atsufficient intervals to document progression of hearing loss orfluctuation in sensitivity, and (f) follow-up evaluations to determinepost-treatment effects.

Audiometric Criteria for Cochleotoxicity:

In this study, criteria were constructed to identify and detect the mostcases of true ototoxicity. The criteria were set to be conservative,because an occasional false-positive identification was preferable toother methods, which could delay detection of the ototoxic process.

In a study of normal test-retest variability of audiometric thresholdsnormal variability was reflected by independent shifts at randomfrequencies. Thus, shifts at adjacent test frequencies are known toindicate more systematic change and increase the likelihood of a truedecrease in sensitivity. Frequency averaging (i.e. calculating theaverage of thresholds across some frequency range) has been advocatedfor detecting decreased sensitivity, and the use of adjacent frequenciesis equivalent to averaging over those frequencies. Another fundamentalconcept is that a decrease, observed on repeated tests, is a validchange. Thus, a shift relative to baseline that was observed at leasttwice is likely to represent a true shift and not normal variation.

Change in hearing sensitivity was computed relative to baselinemeasures. Criteria to indicate hearing decrease during ototoxicitymonitoring were defined as (a) 20 dB decrease at any one test frequency,(b) 10 dB decrease at any two adjacent frequencies, or (c) loss ofresponse at three consecutive test frequencies where responses werepreviously obtained (the third criterion refers specifically to thehighest frequencies tested, where earlier responses are obtained closeto the limits of audiometric output and later responses cannot beobtained at the limits of the audiometer). Finally, any change wasconfirmed by repeat testing.

Baseline Testing

Patient hearing was tested at baseline. The purpose of the baselinetesting was to document the status of hearing prior to treatment.At-risk individuals received baseline evaluations, which were ascomplete as possible. Word discrimination was recommended to be includedin the ideal scope of audiologic practice. The reliability of behaviourresponses was recommended to be assessed during baseline by repeatingselected portions of the evaluation. In addition, results of the firsttest following baseline should be evaluated for inter-test reliability.

The optimal timing of baseline testing depends largely on the drug(s)the patient is receiving. For example, it is known that animalsreceiving large bolus doses of kanamycin do not show histologic evidenceof cochleotoxicity until after 72 hours. Thus, in the absence of moreprecise data, baseline audiometric evaluation of patients receivingaminoglycosides should be done prior to or within 72 hours of firsttreatment dose. Cisplatin can cause observable cochleotoxicity followinga single course of treatment. Thus, baseline measures were obtainedprior to the first dose of Cisplatin.

Monitoring Schedule and Follow-Up Tests

Monitoring tests were scheduled at intervals that enabled the earliestpossible detection (within reason) of cochleotoxic effects. Immediatepost-treatment testing was suggested to document auditory status at theend of drug treatment. Follow-up testing was recommended to be completedat intervals appropriate to detect post-treatment cochleotoxicity or todocument recovery.

ABR Testing for Threshold Estimation

Stimuli: Frequency-specific stimuli (tone bursts of low, mid and highfrequency).

Transducer: Insert earphones were recommended, unless contraindicated,for air-conduction testing. A bone-conduction transducer was needed ifair conduction is elevated (i.e. if air-conduction thresholds aregreater than 20 dB nHL, bone-conduction testing was recommended to becompleted to assess the type of hearing loss).

Protocol: Responses were attempted down to 20 dB nHL. Definition ofthreshold was attempted in at least 10 dB steps. Recording epochs of20-25 ms were necessary for adequate ABR threshold detection measures ininfants, especially when tonal stimuli were used. Many children in theage group birth to 4 months of age were tested during natural sleep,without sedation, using sleep deprivation with nap and feeding timescoordinated around the test session. However, active or older infants insome cases required sedation to allow adequate time for acquisition ofhigh-quality recordings and sufficient frequency-specific information.

Otoacoustic Emissions (OAEs)

Limited

Transient Evoked Otoacoustic Emission (TEOAE): One level (e.g. 80 dBpSPL) click stimulus was completed. Normal distributions for thiscondition for normal hearing are known (see Hussain D M, Gorga M P,Neely S T, Keefe D H, Peters J. Transient evoked otoacoustic emissionsin patients with normal hearing and in patients with hearing loss. EarHear 1998; 19(6):434-49).

Distortion Product Otoacoustic Emission (DPOAE): One level of L₁ and L₂65/55 dB SPL at least at four frequencies. Normal distributions for thiscondition are known (see Gorga M P, Neely S T, Ohlrich B, Hoover B,Redner J, Peters J. From laboratory to clinic: a large scale study ofdistortion product otoacoustic emissions in ears with normal hearing andears with hearing loss. Ear Hear 1997; 18(6):440-55).

Comprehensive

TEOAE: Two levels (e.g. 80 dB pSPL and a lower level) were completedand/or one level using click and multiple frequencies for stimuli, orDPOAE: Use of three levels (e.g., 65/55 and lower levels, as shown byKummer et al (18-19) were completed to obtain DPOAE input-outputfunctions, or at one level for multiple (more than four) frequencies, orComparison of TEOAE (e.g., single level, single stimulus) and DPOAE(e.g., single level): The TEOAE is a better predictor of low-frequencyhearing sensitivity and the DPOAE is a better predictor ofhigh-frequency sensitivity.

Acoustic Immittance Assessment

Probe tones equal to or greater than 660 Hz were used because of thepoor validity of tympanometry when using a low-frequency probe tone withthis age group and the demonstrated diagnostic value of tympanometrywith a high-frequency probe tone.

Unresponsive Patients

In non-responsive patients, objective hearing measures (e.g. auditoryevoked potentials and evoked otoacoustic emissions) was the only meansto obtain auditory information. Although objective procedures provideonly gross information on hearing sensitivity, they are nonetheless,capable of detecting ototoxic hearing loss.

Criteria of Tumor Evaluation

For all endpoints, all treated patients (i.e. who received at least onedose of trial medication) were analyzed for evaluation of response topre-operative chemotherapy and tumour status at the end of trialtreatment. Responses to treatment were defined as follows: Completeresponse (CR): no evidence of disease and normal serum AFP value (forage). Partial response (PR): any tumour volume shrinkage associated witha decreasing serum AFP value, >1 log below the original measurement.Stable disease (SD): no tumour volume change and no change, or <1 logfall of the serum AFP concentration. Progressive disease (PD):unequivocal increase in 1 or more dimensions and/or any unequivocalincrease of the serum AFP concentration (three successive 1-2 weeklydeterminations) even without clinical (physical and/or radiological)evidence of tumour re-growth.

Tumor relapse was defined as follows: Recurrent tumour lesion(s) (localor metastatic) detected by imaging techniques and serial elevation ofserum AFP (at least 3 consecutive rising values, taken at weeklyintervals). In these patients biopsy of the tumour was recommended butnot compulsory. Recurrent tumour lesion(s) (local or metastatic) withnormal AFP, histologically confirmed by biopsy.

Overall survival was calculated from the time of randomization to death.Event free survival will be calculated from the time of randomization tothe first of the following events: progression, relapse, secondaryprimary malignancy or death.

Statistical Considerations

The trial was designed to detect a 25% reduction in the rate of Brockgrade ≥1 hearing loss with a chi-square test, from a 60% hearing loss inthe Cisplatin alone arm to a 35% hearing loss in the Cisplatin+STS arm.The study was statistically powered to answer the main objective of thetrial, which was to investigate if the administration of STSsimultaneously with the administration of Cisplatin significantlyreduces the hearing impairment at the age of

The results of the primary endpoint analysis was presented as rates with95% confidence interval (CI), and as a relative risk with 95% CI. Inaddition, audiograms were evaluated in detail. Time to event endpointswere presented as Kaplan-Meier estimators and corresponding graphs.Overall survival (OS) and event free survival (EFS) were analyzed in anexploratory fashion by multivariate Cox regression taking into accountpotential prognostic factors. Rates were compared by chi-square test orFisher's exact test as appropriate.

The final analysis was completed once a definitive assessment of hearingimpairment was available for 102 patients, or 3 years after the lastpatient was enrolled. OS and EFS endpoints were evaluated at the studyend point and will be continued to be evaluated up to a follow-up of atleast 5 years from the enrolment of the last patient.

Results

Upon completion of the study, it was determined that patients havinghepatoblastoma that were treated with cisplatin but not STS had anincidence rate of Brock ≥1 hearing loss of 67%. Treatment with STSgreatly reduced this number by about half to 37% (p value=0.0033; 95%CI; see FIG. 40). Conversely, patients having Brock grade 0 or little tono hearing loss was above 60% for the STS arm and below 40% for thecisplatin treatment only arm of the study. The reduction hearing losswas most dramatic for Brock grade 2 and grade 3 hearing loss, whichrepresents a significant decline in hearing function, that treatmentwith STS was able to prevent (see FIG. 41). After a median 52 monthfollow-up, no differences in either of event free survival or relapsefree survival was observed for either treatment arm (see FIGS. 42A and42B).

These results indicate that STS was able to significantly reduce hearingloss in pediatric patients having hepatoblastoma. The reduction inhearing loss was most pronounced for Brock grade 2 and 3 patients,indicating that STS is able to prevent significant declines in hearingin these pediatric patients.

1: A method of reducing ototoxicity in a pediatric patient having acancer and receiving a platinum based chemotherapeutic comprisingadministering an effective amount of sodium thiosulfate to the pediatricpatient. 2-6. (canceled) 7: The method of claim 1, wherein the pediatricpatient administered sodium thiosulfate is about 20% to about 75% lesslikely to experience ototoxicity than a pediatric patient notadministered sodium thiosulfate. 8: The method of claim 7, wherein thepediatric patient administered sodium thiosulfate is about 50% lesslikely to experience ototoxicity than a pediatric patient notadministered sodium thiosulfate. 9: The method of claim 1, wherein theototoxicity comprises hearing loss, dysequilibrium, tinnitus, or hearingsensitivity, or combinations thereof. 10: The method of claim 1, whereinthe platinum based chemotherapeutic is selected from cisplatin,carboplatin, oxaliplatin, nedaplatin, triplatin tetranitrate,phenanthriplatin, picoplatin, and satraplatin. 11: The method of claim10, wherein the platinum based chemotherapeutic is cisplatin. 12-18.(canceled) 19: The method of claim 1, wherein the pediatric patient is 1week of age to 18 years of age. 20: The method of claim 1, wherein thepediatric patient is about 12 years of age or less. 21: The method ofclaim 1, wherein the pediatric patient is about 5 years of age or less.22-23. (canceled) 24: The method of claim 1, wherein the sodiumthiosulfate is administered prior to, concurrently with, or after theadministration of the platinum based chemotherapeutic. 25: The method ofclaim 1, wherein the sodium thiosulfate is administered about 0.5 hoursto about 10 hours after the administration of the platinum basedchemotherapeutic. 26-28. (canceled) 29: The method of claim 1, whereinthe ototoxicity is determined by one or more criteria comprising: atinnitus functional index, Brock grading, AmericanSpeech-Language-Hearing Association criteria, or International Societyof Pediatric Oncology Boston Ototoxicity Scale. 30: The method of claim1, wherein the ototoxicity is determined by measuring a hearing loss atone or more frequencies comprising 500 Hz, 1,000 Hz, 2,000 Hz, 4,000 Hz,or 8,000 Hz or a combination of frequencies thereof, wherein a change inhearing is computed relative to baseline measures prior to the patientreceiving a platinum based chemotherapeutic or sodium thiosulfate orboth. 31: The method of claim 11, wherein the ototoxicity is determinedby one or more criteria comprising: a). a reduction in hearing measuredby a 20 dB loss at a single frequency; b). a reduction in hearingmeasured by a 10 dB loss at two consecutive frequencies; c). loss ofresponse at three consecutive test frequencies where responses werepreviously obtained; d). a reduction in bilateral high-frequency hearingcharacterized by: i). a <40 dB hearing loss at all frequencies, whichindicates a grade 0 or minimal hearing loss; ii). a ≥40 dB hearing lossat 8,000 Hz only, which indicates a grade 1 or mild hearing loss; iii).a ≥40 dB hearing loss at 4,000 Hz and above, which indicates a grade 2or moderate hearing loss; iv). a ≥40 dB hearing loss at 2,000 Hz andabove, which indicates a grade 3 or marked hearing loss; v). a ≥40 dBhearing loss at 1,000 Hz and above, which indicates a grade 4 or severehearing loss; or e). a reduction in hearing characterized by: i). a ≤20dB hearing loss at all frequencies, which indicates a grade 0 hearingloss; ii). a >20 dB HL above 4,000 Hz, which indicates a grade 1 hearingloss; iii). a >20 dB HL at 4,000 Hz and above, which indicates a grade 2hearing loss; iv). a >20 dB HL at 2,000 Hz or 3,000 Hz, which indicatesa grade 3 hearing loss; v). a >40 dB HL at 2,000 Hz and above, whichindicates a grade 1 hearing loss, or f). an improvement in a tinnitusfunctional index; and wherein a change in hearing is computed relativeto baseline measures prior to the patient receiving a platinum basedchemotherapeutic or sodium thiosulfate or both.
 32. (canceled) 33: Themethod of claim 1, wherein the administration of sodium thiosulfate doesnot lead to increased serum creatinine or a reduction in glomerularfiltration rate compared to a pediatric patient not administered sodiumthiosulfate. 34: The method of claim 1, wherein the administration ofsodium thiosulfate does not affect relapse free survival or overallsurvival compared to a pediatric patient not administered sodiumthiosulfate. 35: The method of claim 1, wherein the administration ofsodium thiosulfate does not lead to increased incidence of one or moreadverse events comprising febrile neutropenia, infection,hypomagnesemia, hypernatremia, vomiting, or nausea. 36: The method ofclaim 1, wherein ototoxicity is measured at a time of at least 4 weeksfollowing the administration of the platinum based chemotherapeutic andsodium thiosulfate. 37: A dosing regimen for treating hepatoblastoma ina pediatric patient comprising: 1), administering a dose of about 1mg/kg to about 5 mg/kg or about 10 mg/m² to about 300 mg/m² per cycle ofcisplatin; 2) administering about 5 g/m² to about 25 g/m² of sodiumthiosulfate per cycle of the cisplatin, wherein the sodium thiosulfateis administered from about 2 hours to about 6 hours after theadministration of the cisplatin; and wherein the dosing regimen achievesa reduction in ototoxicity when dosed to a pediatric patient compared toa dosing regimen not including the sodium thiosulfate, which is dosed toa pediatric patient, wherein ototoxicity is determined by one or morecriteria selected from: a) a reduction in hearing measured by a 20 dBloss at a single frequency; b) a reduction in hearing measured by a 10dB loss at two consecutive frequencies; c) loss of response at threeconsecutive test frequencies where responses were previously obtained;d) a reduction in bilateral high-frequency hearing characterized by thecriteria: i) a <40 dB hearing loss at all frequencies, which indicates agrade 0 or minimal hearing loss; ii) a ≥40 dB hearing loss at 8,000 Hzonly, which indicates a grade 1 or mild hearing loss; iii) a ≥40 dBhearing loss at 4,000 Hz and above, which indicates a grade 2 ormoderate hearing loss; iv) a ≥40 dB hearing loss at 2,000 Hz and above,which indicates a grade 3 or marked hearing loss; v) a ≥40 dB hearingloss at 1,000 Hz and above, which indicates a grade 4 or severe hearingloss; or e) a reduction in hearing characterized by the criteria: i) a≤20 dB hearing loss at all frequencies, which indicates a grade 0hearing loss; ii) a >20 dB HL above 4,000 Hz, which indicates a grade 1hearing loss; iii) a >20 dB HL at 4,000 Hz and above, which indicates agrade 2 hearing loss; iv) a >20 dB HL at 2,000 Hz or 3,000 Hz, whichindicates a grade 3 hearing loss; v) a >40 dB HL at 2,000 Hz and above,which indicates a grade 1 hearing loss; wherein a change in hearing iscomputed relative to baseline measures prior to the patient receiving aplatinum based chemotherapeutic or sodium thiosulfate or both. 38: Amethod of reducing ototoxicity in a pediatric patient of about 12 yearsof age and under having a standard risk or an intermediate riskhepatoblastoma and receiving a dose of about 1 mg/kg to about 5 mg/kg orabout 10 mg/m² to about 300 mg/m² per cycle of cisplatin, the methodcomprising administering about 5 g/m² to about 25 g/m² of sodiumthiosulfate per cycle of the cisplatin about six hours after theadministration of the cisplatin, wherein ototoxicity is determined byone or more criteria selected from: a) a reduction in hearing measuredby a 20 dB loss at a single frequency; b) a reduction in hearingmeasured by a 10 dB loss at two consecutive frequencies; c) loss ofresponse at three consecutive test frequencies where responses werepreviously obtained; d) a reduction in bilateral high-frequency hearingcharacterized by the criteria: i) a <40 dB hearing loss at allfrequencies, which indicates a grade 0 or minimal hearing loss; ii) a≥40 dB hearing loss at 8,000 Hz only, which indicates a grade 1 or mildhearing loss; iii) a ≥40 dB hearing loss at 4,000 Hz and above, whichindicates a grade 2 or moderate hearing loss; iv) a ≥40 dB hearing lossat 2,000 Hz and above, which indicates a grade 3 or marked hearing loss;v) a ≥40 dB hearing loss at 1,000 Hz and above, which indicates a grade4 or severe hearing loss; or e) a reduction in hearing characterized bythe criteria: i) a ≤20 dB hearing loss at all frequencies, whichindicates a grade 0 hearing loss; ii) a >20 dB HL above 4,000 Hz, whichindicates a grade 1 hearing loss; iii) a >20 dB HL at 4,000 Hz andabove, which indicates a grade 2 hearing loss; iv) a >20 dB HL at 2,000Hz or 3,000 Hz, which indicates a grade 3 hearing loss; v) a >40 dB HLat 2,000 Hz and above, which indicates a grade 1 hearing loss; wherein achange in hearing is computed relative to baseline measures prior to thepatient receiving a platinum based chemotherapeutic or sodiumthiosulfate or both; and wherein the administration of sodiumthiosulfate does not substantively affect relapse free survival oroverall survival compared to a pediatric patient not administered sodiumthiosulfate; and wherein the administration of sodium thiosulfate doesnot lead to substantively increased incidence of one or more adverseevents comprising febrile neutropenia, infection, hypomagnesemia,hypernatremia, vomiting, or nausea.